: generators - everyone has the same issue with generators - the anticipated 'noise'...though I'll add that most onboard Onan generators are no where near as 'loud' as typical generators set outside other RVs... but, yes, many campgrounds limit their night time usage.
: inverter(s) - regardless of whether you have one, or even two, the outcome is the same as if it was a single unit. It sounds like they are trying to keep the basic design the same, similar, and give you the option of the second inverter to power to other items that now need it. The real question is more of battery bank 'storage' capacity, for the 'overnight' usage.
: batteries - whether you need two batteries, or four batteries, really depends more on what you are powering with the battery bank, and for how long. Many of us talk about Inverter 'size', and Solar 'size', but yet if we don't have enough battery 'storage' capacity, we are simply overlooking the greatest need. More batteries equals more overnight capacity.
If I were you, I would simply start with the setup provided by the factory. You might be surprised that their design and engineering teams know more than we might give them credit for.
If you eventually find that your 'off-grid' needs for power are well met by the current batteries, then fine. If you find that you are lacking the amount of storage, you can either change to 6v batteries, or even move to 4 - 6v deep charge batteries wired in series, and parallel, like most larger coaches.
If you have the AGS, you'll find that it's a great tool to provide an easy-to-use off-grid RVing experience. It will crank and run your generator, automatically, when needed to charge the battery bank. You can also set it to limit starting during certain overnight 'quiet time' hours. Simple. and Remember, many folks 'worry' about the residential fridge the most, as if just because it has no power for several hours that everything in it will somehow suddenly 'go bad'... but a fridge is just a big cooler, it will keep things cold for many hours with no power, worst case scenario.
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
110,000+mi since '14 - US, Alaska, Canada (also, '14 Gulfstream Amerilite and '07 ForestRiver Rockwood) : )b