pabst photo? that's my beer!(and the beer of hipsters, but i don't hold that against them, or the fact that they jsut sold out to russians)
I find myself doing this from time to time, and it sounds like you told the client what i always tell them with these things. You did very well, and i'd certainly be pleased with that result. I second what Mt Spokane says, but of course there almost always seems to be room for improvement with such things. I monday morning quaterback the hell out of my work sometimes.
As for the guy talking about pano, i would have done it, but then i would have taken some single exposure stuff as a safety net. you would think that the people would know how important it is try and make it work for the photo guy, and extension the client(your friend) but people just don't behave. i don't have much faith that people can even post for a shot like this without giving me the finger, or some other sly move. maybe even pull a "Teen Wolf" type of background thing(it's a thing, google it). i wouldn't put it past many.
anyway, good work, i'm sure they will be pleased.
Back when I was at uni, we had quite a few group shots over the years, one guy on the course enjoyed whipping a testicle out to see if it would get noticed afterwards. One may have ended up enlarged on the wall in the department during open days for prospective students...
To the OP, you did very well given the circumstances. Did you ask the bride and groom to crouch or did they just automatically do that?