Eavan and Caitie look suspiciously like
Evan and
Katie, i.e.
EVan and KAYty.
Caitria could be a form of
Catriona, but there's a difference of opinion there - the books say ca-TREE-on-a, but the only ones I've ever known have said CATE-ree-OH-na. So I'd guess CATE-ree-a.