Kerfoot is a nothing burger. Maybe the Leafs get a mid round pick for him from a team desperate for a 3rd line center. Johnsson had some promise, but is coming off a serious injury and didn't take the next step this season that many thought he would. Again, seems like a player Toronto might get a mid round pick for if they wanted to dump salary. Andersen is a little bit more of a wildcard. I think he's a good goalie, but he's set to hit FA and I have zero interest in giving him a long-term (Bobrovsky lite) type of contract.
So in summary, those pieces do little for Buffalo, those are the type of middling pieces Botterill might have settled for, but I'd be surprised if Adams made that type of deal. If Toronto wants to move the 15th pick then there could be a deal there, but the thought of giving up a valuable asset for Ristolainen doesn't seem to sit well with most Leafs fans.