Ground Switching For Mobile Application--Only Necessary For Inverter/Chargers w/ 120 V Passthrough?

desert_sasquatch

Hi yall!

So I'm about to set up my trailer with an electrical system meant for boondocking but (if it's not too hard or expensive) with the capability to plug into shore power.  While I plan on using solar, I am sizing my battery bank such that I know I'll need to use a generator or shore power some days.  

In short, my system will be:  400 AH 12 V w/ LiFEPO4 batteries sporting the Overkill Solar BMS, and 120 VAC (which will be used very sparingly) provided by the Giandel 2000 w pure sine inverter (it's a "car inverter").  The batteries, when not charged by solar, will be charged by two 45 A 12 V progressive dynamics LiFePO4 chargers.  If that's possible with four 100 AH 12 V batteries.  Otherwise I'll probably switch to a 200 AH 24 V system, charged with two 24V 25A Cotek battery chargers.  

My question, though, is about ground switching.  Which I'm still quite confused about.  I understand that high-end inverter/charger combos like the Samlex EVO and the Victron Multiplus have some kind of automatic ground switching that kicks in when you plug or unplug from shore power (or maybe from a generator?)  What I don't understand is:

1)  Is ground switching only something that matters when an inverter/charger offers "passthrough" AC current?  Or is it a concern even with the battery chargers like the Progressive Dynamics one I linked?

2)  I've heard that some "car inverters" (that is to say, inverters with "normal" 120 V 3-prong outlets) come with GFCI outlets, but that they require some sort of special wiring to make those GFCI plugs work.  Does anyone have any brands they'd recommend?  How important is this feature in a mobile application?

Thanks so much yall!