No additional picks needed for them to take Kerfoot.

Protect 8+1 (that includes Holl). Sign Hyman after exp draft. Mikheyev is exempt.

I doubt Palmieri signs that deal.

Sandin, Anderson and likely Liljegren will all be ready to graduate next season.

Maybe, but they might not want to go for Kerfoot with his cap hit? Might take a little persuasion, but don't expect all that much.

It's Kerfoot or Dermott (if they go 8+1).

If Dermott is taken, then Sandin fills that gap (and I'm a big Dermott fan).

I really don't see the Leafs sending any picks Seattle's way, unless there is a roster shift, like Forsberg acquired (just an example).

Every ACGM for next year has teams sending picks to Seattle, when in reality it may happen a handful of times.

Leafs will lose a decent player, but they can cover any loss either internally or through FA.

Then who would they go with?
Hyman is a pending UFA. If Seattle takes him he could sign back with the leafs a week later.
Mikheyev is exempt.
Holl can easily be protected. Protect him while going 4-4 (the big 4 forwards plus Rielly Brodie Muzzin Holl). Unless you are concerned about Dermott. He make be taken. But it's equally possible Seattle take Kerfoot over Dermott anyways due to they fact he's better and is a forward, which may be hard for Seattle to find.
So if you want Seattle to take Kerfoot over Dermott, I'm sure you could do what Buffalo did and send them like a 6th. That would probably be enough. If not I don't see what it's even that bad to loose Dermott with Sandin coming up.