Is it OK if you find characters with the same name, but in different realities/fandoms/worlds?

I personally think it's fine. Even the music industry finds it OK - google for a song called 'Call Me', or 'Heaven', or really generic titles. You'll find TONS. The industry says that, if you want to argue about copyright, it's that the idea of the song - melody, lyrics, arrangement - are the parts covered under copyright. The other parts of it - titles, for example - are free for use by anyone.

(Important note: I took a class about the business of music under a songwriter, formally a lawyer, who was in the biz in the last decade. Therefore, don't use this text to quote or reference, especially for homework! Feel free to correct me if you (think you) know better.)

It has happened in Epics, Short Stories, or sometimes the same name used in both - and by different authors, of course. Haven't seen any authors go head to head to say which character was the REAL character, the one true character to be christened 'Xenohelix', so on and so forth, but it's just as much an argument about Avril Lavigne's 'Girlfriend' with 1979 Rubinoos song 'I Wanna Be Your Boyfriend'.

*shrug* I still think Toa Varian has the making of awesome, but my mind still fritzes and says

-<dd>