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