Well....maybe? it depends. If were talking about the batteries that are going in the truck at some point for truck systems, oh absolutely...Actually, based on that info in you quoted me above, I'm going to be curious to see how my truck handles the sub zeros this winter. Its only ever seen teens, maybe single digits....Whatever house battery chemistry you select, you'll want an insulated battery box with some type of automated heating circuit for when it's unattended for weeks. Yea! Another project within a project.
But, so the idea is all systems (including fuel) will be inside the insulated portion of the 'house' (er, trailer). Plan is to have 4" of insulation. So a double wall of sorts. Now, there will be a false wall between the actual house and batteries/fuel/gen/etc. of course for safety purposes. But, the items will still be inside the overall insulated home. The house would always be heated. Even if tanks are empty. Reason being is, well, ever see how fast a stick house degrades from not being lived in (ie, no heat)? So, anyway, always having heat, pending a loss of power or fuel supply, the false wall would provde enough of a barrier for safety reasons, but still allow heat to seep through, although much cooler, but not freezing. So in theory, batteries, genset, fuel, etc.. would all always at the absolute worst, be above 0. I could set the house temp to 40 while gone, and with outside vents, the 'systems closet' you could call it, would certainly be cold, but probably not below zero by any means.
Maybe it would work, maybe not... that's the theory. I do like the battery heater idea, but I dont plan on having things exposed. Stuff just doesn't last as long in extremem climates. But, heaters for the planned aux batteries in the truck will absolutely occur. And, likely those aux truck batteries (either 2 or 4) will also primarily power battery heaters for the starting batteries, and the future planned diesel heater (for when I'm away from a power source in dead of winter, or to prewarm the cab!).
As of now, I would think for the house, I could get away with a diesel coolant heater and one (maybe 2?) radiators with a temp sensing fan to keep the underbelly above freezing. A diesel air heater (yes two systems...but....) could provide heat, and a diesel genset (since I'm already running diesel heat devices) could be used to charge when I'm not on shore, or theres insufficient solar (pretty much most the winter probably). Thus far I think I am going to stick with LP for cooking. I cook a lot and just like cooking with gas. 2 20# tanks can last a summer, so that would be fine. Then, just need to decide on refer. 12v is probably the way to go...if the numbers can work ok. Anywhoo...current thought process.