that is just a converter, it will charge your batteries. Most of your lights are probably set up as 12V so no need for the Inverter.
If you start adding new things that need 110V then you need to get an Inverter if you want to use them when not connected to shorepower.
I really love all the tongue and groove, mine will get a bit of that too.
You say you have it registered as an RV in BC, do you mind me asking how much you are paying a year? What kind of coverage?
I'm still trying to decide if it is worth jumping through all the hoops to have mine registered as an RV. If I keep it as "Bus for Pleasure use only" it costs me around $1400.
We should organize a Western Canada Skoolie meet