With >99% certainty:
The cooktop (and conventional oven, if it has one) is propane only. Super simple technology, probably no pilot light or sparker for the burners (i.e. match light).
The fridge is two way, propane and 120V electric, and probably needs 12V power from the house battery for the control circuits.
The water heater is likely propane only, not tankless. In general people with RVs with tankless water heaters are not always the happiest with that setup, which might partly be due to the specific water heaters that get installed. The water heater may be DSI (i.e. electric) ignition, in which case it also needs 12V power, or it may have a pilot light and manual thermostat. It's possible it might also have a 120V element in it, but I would suspect it does not.
The furnace is propane, with 12V fans etc. powered by the house battery.
You do have two 12V electric systems. One is for the chassis only, and one is for the house stuff. There's some sort of a combiner circuit to allow the house battery to charge from the engine alternator; there are a few different designs to do this, but one common way is to have a solenoid (relay) that closes with the accessory/run circuit from the ignition. Often there's also a button on the dash to manually connect the batteries together at other times, mainly as a sort of built-in jump starter should the chassis battery be dead. There is also a converter that charges the house 12V battery when connected to 120V power. Between these systems, I wouldn't put a jump starter pack super high up on the list of priorities, though they can be handy things to have.
The generator is almost certainly gas powered, and if not it would be propane powered. I don't think anyone would put a diesel generator on a gas motorhome, especially as diesel generators are more expensive. If gas, the generator pickup in the fuel tank is usually built such that it will not get fuel if the tank is less than about a quarter full (i.e. it doesn't extend all the way down the tank) so that you can't strand yourself by running the generator too long.
Depending on the generator model, it may not have an oil filter.
