LV5048 – Off grid RV – Can the utility charging feature be customized via settings example: say I am visiting a relative and they usually only have 120V 15A available and would like to modify the max utility draw not to exceed value….?

Yes you can adjust ALL settings.

LV5048 – Looking for Off Grid – How many Vac/Amps per leg?

If running a single phase 5000W/120V=40A
If Split phase 2500W per phase/120=20A
In 3 Phase you will need 3 inverters (15kw, hence 5kw per phase =40A