Converter = 120Vac to 14Vdc
Inverter = 12Vdc to 120Vac.
Likely came with a bigger converter (if that's what you're talking about) to supply the batteries you have. The rule of thumb for design work is a 100% overhead so if 40 amp is considered the typical draw, because of all the loads you have potentially, then an 80 amp converter makes sense.
When you try to reverse engineer something like that, be careful. The engineers often know what they're doing.
None of the items you mentioned draw much current from the batteries but I suspect there's an INVERTER somewhere with several outlets. They aren't very efficient and the higher amp converter would be to replenish the batteries quickly on shore power if you used the inverter a lot while boondocking.