The best move for Anaheim (by far) is to trade Vatanen directly for a ELC contract forward that is expansion exempt.
Nothing in the league makes more sense for both teams than:
Kapanen for Vatanen
Leafs probably need to add a 1st or 2nd, but given Anaheim's lack of bargaining power and the immaculateness of the fit, I'd still take it straight up.
Edit: Yes I know some will say he isn't a perfect stylistic fit - but you're really being way too spoiled here.
Leafs need a top-4 right handed defender. They have a bad defensive unit that was bottom-5 in the league and has been for years.
Vatanen is a very good top-4 right handed defender (a legit #3) with lots of experience under his belt including deep into the playoffs.
Yes you want Manson, you want Hedman, you want Doughty - but we have Vatanen and he's way more available than defenders of his stature typically are.