I like Llyr
a lot - though not spelled Lir
. I think I can see it working in real life, but that might just be because I really want it to. But I do understand your concerns about spelling and pronunciation. Honestly, I think it does sound better with the proper Welsh double L sound, but that's impractical on this side of the Atlantic, and it's okay otherwise.. I don't think people will think it's made up, it's not that strange. To me, Lir
looks more made up than Llyr
, but I guess if someone's completely unfamiliar with Welsh names it could look really odd with the extra L and the Y.
What about Lear? Shakespearean connotations ground it a bit and it looks a bit more familiar and traditional that way.
eta: I think what bugs me about Lir
is that I want to pronounce it rhyming with "fir" or "sir."