I don't see how King's Rock helps Togekiss, as it is supposed to add a 10% chance of flinching on moves that do not have it. I'm not sure Serene Grace boosts it either. In my opinion, running Leftovers benefits you more, as it provides enough recovery to pull a Nasty plot, without taking a turn for Roost.
You could also use Life Orb, though I don't recommend it here.
As far as Slowbro goes, I think Scald-burn and Foul play is a bad combination. Since Slowbro is already a tank, you can tweak the EVs more to defense and run a Calm Mind set. This way, even if still weak to dark type attacks, you keep your bro alive, and possibly slow sweep. You will be able to deal with Scizor, Talonflame and Landorus-t better.
I would keep Heal Bell on Celebi, because status pretty much cripples Excadrill and Lopunny.