If you LOVE Zachary then use it. My brother and cousin have the same name, we saw them a lot growing up and it was never a big deal. If you're worried maybe chat to you BIL/SIL about it.

Oliver is very popular atm.
Gabriel is a bit femine for me.
Love Wilder, very cool, bit differnt.

Also Love Dashiel (Dash).

What is your DS's name?