Re: transfer switch for off grid power
Must be having a senior moment as I don't see why you need two transfer switches to change your AC feed between generator and inverter.
A transfer switch has one output and two inputs. The output goes to the AC breaker box. One input goes to the inverter's output, one goes to the generator's output.
If you have one of the inverter/chargers it has AC IN which means it has a built-in transfer switch.
Ground wiring should not be affected by any transfer switch, as all grounds should be connected together at all times and terminate in a single Earth ground point. The only time you get in trouble with this is using an MSW inverter which can not have the AC neutral-ground bond. In that case you leave the bond out and let the neutral "float". Check to make sure the generator doesn't already have this bond in any case, as you don't want two such connections.
Again, I don't understand what you're trying to achieve with two transfer switches. Is grid power available as well?
1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.
Ohm's Law: Amps = Volts / Ohms
Power Formula: Watts = Volts * Amps