#1 Oliver- Fantastic Name. I like it A LOT more than any of the other options. My vote definitely goes here.
#2 Gavin- Solid name. I like it. But doesn't work well with Ava.
#3 Hudson- I'm pretty mediocre about it, but I think it could grow on me.
#4 Hunter- Hmm.. maybe it could grow on me. Feel a bit last-namey to me though. Archer would be a cool alternative. Or what about Bowman?
#5 Jackson- I've never been a fan of this as a FN. Jack is pretty cool, but I don't like Jackson much. Unless he actually is the 'son of Jack', than it'd be cool.
#6- Mason- Mason is a name I just don't like... at all.