I'm honestly leaning towards Mid for Lapras. Yes, it has a very low encounter rate in Village Bridge, but it may well be the best late game water type. Comes with that lovely Ice Beam for Drayden, cockblocks Marlon (though he's piss easy anyway), and its sheer bulk, all around good stats and great coverage moves including Psychic, Drill Run, Body Slam, whatever floats your boat, kind of makes it worth it for my money. Max Repels make it so much easier to find.
Other late game water types... Basculin? LolDamp Jellicent? Fucking Mantine? ALOMOMOLA? Starmie? Ok, yeah, Starmie is awesome.