You need to approach your problem from the other end.
Select the heaters that will provide the amount of heat you need. This will set the voltage that you need to deliver, and the wattage consumed by each heater.
Then with an estimate of the time they will run each night (or you can measure it accurately if they happen to be 115AC heaters), the battery bank size can then be sized. If you want backup storage for 1 or more "no sun" days, that will increase the battery bank size.
With the final bank size and either a geograpical location or the low solar insolation data for that location, the PV array can then be sized.
Whether or not one of the powerwize systems will work, would be based on that final array and bank size. An educated guess says no, you will probably need a custom sized unit.
I would suggest that you give up the idea of removing the batteries from the system and carrying them to the rooms. Even if you find a 12 volt heater that would do the job, you might need 2 or more batteries per room to power them. And even sealed batteries can give off fumes, particularly when something goes wrong.
Leaving the batteries in the PV system and providing wires to the rooms will save you a lot of work in the long run.
