I'm not sure why people think Kingler is good versus Lapras.
Yes, Metal Claw is super effective vs. ice. But it's not very effective vs. water, so it only hits Lapras for neutral damage. When taking into consideration that Kingler doesn't even get STAB on the move, his only upside versus Lapras is that he resists ice.
Fire types also hit Lapras neutrally, while also resisting his ice-type attacks. The big difference is that they get STAB on their moves, though. This makes them better to take down Lapras than Kingler will ever be.
Jolteon is okay too - he'll hit Lapras harder than fire, but at the same time he won't resist ice, so you need to dodge more.