Keep Holland. We have Center prospects that are NHL ready. Bolland/Mclement are both UFAs who could leave in the off-season.
Anahiem simply had one of the best and deepest prospect pools with guys like Etem, Silfverberg, Palmeri, Smith-Pelley all in their 1st or 2nd year meaning they simply didn't have room to break in another young winger. It doesn't mean Holland couldn't be switched to the wing.
Reimer will simply be to expensive to a backup. Trade him in the off-season.
trading Reimer would be a mistake because if Bernier gets hurt, the Leafs would need to trade or sign a capable backup. It's good to have a good backup for any potential injuries and if the Leafs continue to allow 40 + shots per game, they will need 2 good goalies.