Scarfchomp can give that core trouble if it predicts properly, e.g. you predict D-claw and it EQs your T-tar/Mawile on the switch in. It won't necessarily OHKO, but it will severely cripple whichever it is (and of course, you'll have to switch to Dnite afterward to avoid the 2HKO). Same deal for dragonite on a dragon claw.Alright, thanks! jw, what Chomp are you referring to?
LO Chomp can OHKO any of those three pokemon (except Dnite with multiscale up), and of course can change moves as it needs to. But, it won't be able to come in on +1 Dnite and threaten to outspeed like Scarfchomp, so there's that. It doesn't have to be a huge problem if you predict correctly, it's just that the penalty for clicking the wrong button is huge.
That said, while bold lefties Clefable is only 3HKOd by LO Chomp's EQ, it can't switch into Chomp and threaten it out because it can only 2HKO in return. But it overall takes hits from Chomp much better than your other mons, and perhaps after some life orb recoil, you could switch in and OHKO. It's really hard if not impossible to properly counter Chomp though, so Clefable seemed the best option at least until you pick more mons.