Residential Frig Install ??

Existing is fine.

As long as you don't exceed the inverter's 2K watt limit when adding the fridge to whatever else the inverter happens to be powering your current inverter should suffice. Whether you need additional batteries depends on amperage demand and length of time you intend to power these devices with your inverter without draining batteries below 50% capacity.

Depends on how long you want to go boondocking. We have a Samsung 197 with 4
house batteries and 2000 watt modified sine. Have used for about 1 1/2 years with no problems. If off the grid I run the generator for about 1 hour in the morning and 1 in the morning we're good. The alternator on the MH keeps the everything charged while we are driving.one of the best mods we've done.