A decent welder should be able to turn out a trailer hitch <=> outboard motor bracket in under 15 minutes. It's not like you'll need much more than a modest fishing outboard to get through flooded spots.
jeep snorkels are for air intakes for engines. electric cars don't have air intakes. they have air cooling for batteries... I suppose you could snorkel those.
I guess water propulsion... and a rudder?