Probably be a good idea to add a couple house batts. If some 12V device is left on overnight at least you won't be walking. You have to know where you're camping...some don't allow genset beyond certain hours....some require stacks (vertical genset exhaust), and some are just free-for-alls. Obviously, most campgrounds will have power poles. So if you go from pole to pole...you could get by without much water capacity or house batteries.
Being able to parallel your house batteries could get you on the road too. I suppose one could carry the "redundancy" thing to the extreme?
Sounds like you have it sorted out. I'd set aside some room for house batts just in case...you may wish to sell the coach, and typically, house batts are considered a necessity. I'd also keep the genset on a separate battery...with capacity to parallel to the cranking batteries so that the genset could be cranked in the event of generator battery failure...I have that ability...it called jumper cables. However, the wiring is in place for generator parallel....it's the old AC condensor fan motor cable. Plenty big enough. One of these days I'll figure out which switch operates the cable.
Inverters and generators are boarderline incompatible. The inverter will come with detailed instructions for installation. 50 pages of instructions.