Those 2016 creature-Toa unity things, how exactly do they unify in-universe...? I can't image the Toa and creatures have pegs sticking out of their backs and the creatures having random holes in their bodies.

How exactly doe Ikir support the weight of Tahu? Shouldn't Tahu fall down to his untimely death?

And who goes up to a giant scorpion and goes 'Yes, I want to unify with that and have it on my back!'

Assumption: The 2016 story is about the dangers of unifying with random creatures and other things you find in the wild, and Umarak is not one being, but a gestalt entity made up of thousands of much, much smaller creatures that fused together and happen to be naturally inclined towards evil because the story's about the danger of randomly uniting with things and Umarak represents that danger. In fact, Umarak happens to be made up of these much smaller beings: Umbra, Mata Nui, Ackar, Radiak, Avak, Krika. UMARAK. THE HUNTER. OF CREATURES! For some reason. Probably because they laughed at him in phoenix language, shark language, jungle bug language, scorpion language, earth mole language, and earth mole language limited edition version. Now, of course, Umarak, being multiple beings, is often very conflicted about what to do, so Umarak splits into five identifiable and extremely memorable villains: Skull Grinder, Skull Warrior, Skull Basher, Skull Slicer, and Bad Guy 2006, so that Umarak has an easier time battling the six Toa. However, as you noticed (if you can count), the Toa have six people and Umarak is made up of six people but Umarak has split up into five people. So the teams are a bit unbalanced, so let's say Brutaka comes in and dips himself in Umarantidermis for plot convenience, but then there's the problem of Brutaka's sole purpose being poorly-done foreshadowing, like how Makuta will awaken and how Ekimu will reign over all with a stone fist because iron isn't an element in G2 and it would be really weird if Ekimu's fist was made of iron. Let's not have Brutaka. Let's add someone more interesting, like Turaga Dume. Now, Turaga Dume really fits as a G2 villain, because his name is literally doom, so it's just on-the-nose enough for G2's naming schemes. But then again, Turaga are basically BIONICLE Old People, and maybe that's a bit unfair to be placing him against the Toa. Let's instead place a special guest: The beloved character from the 2002 BIONICLE-Knights' Kingdom-Hero Factory-Slizers-Weirdly human looking crossover spin-off line: Galidor himself. Now, Galidor's a character with absolutely no attachment to anything, because he doesn't have any free studs or ball joints, meaning that he hates all things that look like not Galidor, which is everything but Galidor, and not to mention, the existence of Galidor means Gali has to go, as we all know kids are too confused by the same four letters appearing in both names. After all, they might think Gali is a door or that Galidor is a door to the realm of Gali, which is basically a neverending ocean with giant Gali statues on the seafloor. But this means that the Toa now have five people, and the bad guys have six... so here's what we do: We send THE TOA on a quest for the SEVENTH TOA! But we need a sixth toa before we can quest for the seventh Toa, so we hire a random Toa nobody cares about like Tuyet to cover that up, while explaining that Tuyet is from an alternate dimension where Mata Nui destroyed all who stood in his way. Anyway, this seventh Toa turns out to be not Takanuva, but in fact, Kulta the Skill Grinder, but then that poses a problem, as Kulta is aready on Umarak's split-down team, which also means he's a part of Umarak, which also means he's a part of Umbra, Mata Nui, Ackar, Radiak, Avak, and Krika... Ah! THEY FIND! UMARAK. THE HUNTER. OF CREATURES! For some reason. Probably because they laughed at him in phoenix language, shark language, jungle bug language, scorpion language, earth mole language, and earth mole language limited edition version. Now, of course, Umarak, being multiple beings, is often very conflicted about what to do, so Umarak splits into five identifiable and extremely memorable villains: Skull Grinder, Skull Warrior, Skull Basher, Skull Slicer, and Bad Guy 2007, so that Umarak has an easier time battling the six Toa. However, as you noticed (if you can count), the Toa have six people and Umarak is made up of six people but Umarak has split up into five people. So the teams are a bit unbalanced, so let's say Brutaka comes in and dips himself in Umarantidermis for plot convenience, but then there's the problem of Brutaka's sole purpose being poorly-done foreshadowing, like how Makuta will awaken and how Ekimu will reign over all with a stone fist because iron isn't an element in G2 and it would be really weird if Ekimu's fist was made of iron. Let's not have Brutaka. Let's add someone more interesting, like Turaga Dume. Now, Turaga Dume really fits as a G2 villain, because his name is literally doom, so it's just on-the-nose enough for G2's naming schemes. But then again, Turaga are basically BIONICLE Old People, and maybe that's a bit unfair to be placing him against the Toa. Let's instead place a special guest: The beloved character from the 2002 BIONICLE-Knights' Kingdom-Hero Factory-Slizers-Weirdly human looking crossover spin-off line: Galidor himself. Now, Galidor's a character with absolutely no attachment to anything, because he doesn't have any free studs or ball joints, meaning that he hates all things that look like not Galidor, which is everything but Galidor, and not to mention, the existence of Galidor means Gali has to go, as we all know kids are too confused by the same four letters appearing in both names. After all, they might think Gali is a door or that Galidor is a door to the realm of Gali, which is basically a neverending ocean with giant Gali statues on the seafloor. But this means that the Toa now have five people, and the bad guys have six... so here's what we do: We send THE TOA on a quest for the SEVENTH TOA! But we need a sixth toa before we can quest for the seventh Toa, so we hire a random Toa nobody cares about like Tuyet to cover that up, while explaining that Tuyet is from an alternate dimension where Mata Nui destroyed all who stood in his way. Anyway, this seventh Toa turns out to be not Takanuva, but in fact, Kulta the Skill Grinder, but then that poses a problem, as Kulta is aready on Umarak's split-down team, which also means he's a part of Umarak, which also means he's a part of Umbra, Mata Nui, Ackar, Radiak, Avak, and Krika... Ah! THEY FIND! UMARAK. THE HUNTER. OF CREATURES! For some reason. Probably because they laughed at him in phoenix language, shark language, jungle bug language, scorpion language, earth mole language, and earth mole language limited edition version. Now, of course, Umarak, being multiple beings, is often very conflicted about what to do, so Umarak splits into five identifiable and extremely memorable villains: Skull Grinder, Skull Warrior, Skull Basher, Skull Slicer, and Bad Guy 2008.so that Umarak has an easier time battling the six Toa. However, as you noticed (if you can count), the Toa have six people and Umarak is made up of six people but Umarak has split up into five people. So the teams are a bit unbalanced, so let's say Brutaka comes in and dips himself in Umarantidermis for plot convenience, but then there's the problem of Brutaka's sole purpose being poorly-done foreshadowing, like how Makuta will awaken and how Ekimu will reign over all with a stone fist because iron isn't an element in G2 and it would be really weird if Ekimu's fist was made of iron. Let's not have Brutaka. Let's add someone more interesting, like Turaga Dume. Now, Turaga Dume really fits as a G2 villain, because his name is literally doom, so it's just on-the-nose enough for G2's naming schemes. But then again, Turaga are basically BIONICLE Old People, and maybe that's a bit unfair to be placing him against the Toa. Let's instead place a special guest: The beloved character from the 2002 BIONICLE-Knights' Kingdom-Hero Factory-Slizers-Weirdly human looking crossover spin-off line: Galidor himself. Now, Galidor's a character with absolutely no attachment to anything, because he doesn't have any free studs or ball joints, meaning that he hates all things that look like not Galidor, which is everything but Galidor, and not to mention, the existence of Galidor means Gali has to go, as we all know kids are too confused by the same four letters appearing in both names. After all, they might think Gali is a door or that Galidor is a door to the realm of Gali, which is basically a neverending ocean with giant Gali statues on the seafloor. But this means that the Toa now have five people, and the bad guys have six... so here's what we do: We send THE TOA on a quest for the SEVENTH TOA! But we need a sixth toa before we can quest for the seventh Toa, so we hire a random Toa nobody cares about like Tuyet to cover that up, while explaining that Tuyet is from an alternate dimension where Mata Nui destroyed all who stood in his way. Anyway, this seventh Toa turns out to be not Takanuva, but in fact, Kulta the Skill Grinder, but then that poses a problem, as Kulta is aready on Umarak's split-down team, which also means he's a part of Umarak, which also means he's a part of Umbra, Mata Nui, Ackar, Radiak, Avak, and Krika... Ah! THEY FIND! UMARAK. THE HUNTER. OF CREATURES! For some reason. Probably because they laughed at him in phoenix language, shark language, jungle bug language, scorpion language, earth mole language, and earth mole language limited edition version. Now, of course, Umarak, being multiple beings, is often very conflicted about what to do, so Umarak decides that others should share the ame burden, the burden of being more than one creature being fused, unified, melded together, and forcefully fuses the Toa and creatures together under the guise of giving them more power... and now, the Toa are... Toa Chordika. Like Hordika, except the animalistic part is way more literal because they have animals fused to their backs and they also happen to be excellent singers, like how they sing about UMARAK. THE HUNTER. OF CREATURES! For some reason...