1. The ya in the Russian is, if I am not mistaken, not pronounced that way after an l. So it's Solaris, not Solyaris. Perhaps a native speaker could clarify this?

Perhaps anybody who's ever studied Russian can clarify this. You're wrong. The 'y' is not strictly pronounced as the 'y' in English, but it indicates a palatization, or 'softening,' of the preceding sound, which sounds a lot like a 'y' after the letter. Anyway, a Russian who speaks English would typically choose to spell it 'Solyaris' rather than 'Solaris.'