I don't think it's that big of a deal to have the same ending. Those two names do sound a little matchy though, because of the L sound in the middle in addition to the A ending. But I would still use it. It won't seem like you tried to match them on purpose because you have a third child. I'd probably advise against it if they were twins or something, but I think for two out of three siblings, it's fine.
Re: sibs- ending in same letters?
BFP#1 10 wk missed mc
BFP#2 DS born at 40+2 on 8/14/12 BFP#3 DD Born at 39+3 on 5/13/14