ATX, mine came with toppers as an option I checked when I ordered. I will definitely have them from now on seeing as I have pine trees lining my property and have to clean them off every time we pack up. As far as brand... someone else here would be more apt to know that.
As far as the genny: I would think it would run one, but not both AC units. I'd post in the forums and find out from the Peanut Gallery!
2013 GMC Savana 2500 FBI Edition
2015 Rockwood 8327SS stuffed with 5 kids!
Nights camped 2014: 48