I have no experience with reheating a whole pork butt. (Sure... I've had left overs and I've re-heated it but I didn't have the pressure of a wedding dinner to worry about) I sure haven't done 7 or 8 of them at once. But from what I've read here. Most say to go ahead and pull and re-heat with a finishing sauce. I think the idea is that to re-heat it whole takes so long it's almost re-cooking it. When it's pulled it gets to a serving temp way faster. I'll be looking for those with more expertise than I have to chime in though.
By the way...that must be a huge wedding? I think that most people use a quarter pound per serving as an average? My experience that the average pork butt is 12 - 14 pounds. So, one pork butt is roughly 48 servings. Seven would be 336 servings. I guess that's not a huge huge wedding but pretty dang big.
Be sure and post lots of q-view for us!!
Best of Luck!!