I think it is fine, but prefer
Lea or Léa. The sound is nice and I really like its looks, but I can't say I'm a fan of the most possible meaning. I like most of animal names, but "weary" is already too much for me. :D
I don't really get
Leah nicknamed
Lia - their length is almost equal and I pronounce them the same way.
Sofia "
Lia" is very weird, too.
Lia works very well as a nickname for
Liliana,
Amelia and
Emilia, though. I think I prefer
Liliana "
Lia" - it looks most logical. How about
Lilian or
Lilias? They'd both look great with
Isabel and
Nicholas!