>>28778249Speaking objectively water fighting is terrible for current Feraligatr, as without movepool expansions he is fucked with only a defensive typing to use.
Speaking for headcanon flavor wise, hey let's give Meganium grass ice, because fuck yeah! It's a strong offensive typing and it could get ice beam and Blizzard!!!
Realistically speaking, even mons ingame can be fucked up royaly by their typing. Slow ice types, slow fire ground and fire rock, frail bugs without enough offensive fire power, defensive rock ground and grass ice can make for shity Pokémon, heck Exeggutor with grass psychic fell HARD from grace on gen 3,lets never forget how hard his fall from its status as best grass type was.
Water Fighting isn't terrible, Poliwrath is really fucking good, but this doesn't really translate to Feraligatr, I also forgot about focus punch and Dynamic punch BTW.
Sheer force focus blast and dynamic punch FTW!
Dragon or Dark are competent enough typings, they don't overlap with water and you get accessible moves to abuse ingame with a decent set of neutralities.