HELP - boy's name (due SOON!)

[Junglemum]

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?

[TeniBear]

Zachary/Isaac - I agree with Junglemum, if you love Zachary, then use it. If Isaac gets called Zac, maybe call Zachary "Zacky" (IYKWIM?)

Oliver - I looove this name
Gabriel - This was one of the names on our list for a little bit when I was pregnant, but looking at it again I don't really like it anymore.
Wilder - Nope. You asked for brutal, so I don't feel too bad at saying that I hate this name. Wil, yes, that's nice, but not Wilder. Sorry

[Sabbey]

If you love Zachary, then use it. I don't see a problem.
Out of the other names you mention I only like Oliver.