I think I'll rule out the Georgetown Marriott so you don't have to fight about it anymore.
Like I said, being close to Foggy Bottom isn't important and I don't think there is a ton for the family to do right there and it is kind of far to a metro stop.
As for the Zoo, we've been there several times and I imagine in July it will be too hot for us to want to go again.
I'm leaning towards the Renaissance as it is a contender for my overall favorite brand and I don't think I've ever had a bad stay at one. Wife is still wanting to try the Ritz though since we've never stayed in one. I might just do it without the club. Is it possible to buy club access for a single night just to try it out?