well it depends which gender you're using them for.
Hollis is a -boys- name in my opinion. and therefore, yes, use it for a boy and not a girl. it'd sadden me to see one of my future sons middle name son a little girl.
Avery has grown on me for a girl, mostly because I have a neice called
Avery. but yes, it is a boys name and I think I prefer it on a boy.
and I just dislike everything about
Ivy.