I don't think the idea is getting one guy, nor to necessarily replace Kerfoot directly, more than to find a different mix (and to maximize value on Kerfoot).
If we are looking at 2 guys, one will be a center and one will likely be a 2LW or a 4LW.
Getting the right mix is tough. I think ideally, the center can both PK and PP. Both units need a guy who can take draws. Steel does not have a ton of experience as a PKer, but I can see him being the best fit in that regard. Jarnkrok is solid too, but he may be costly. Tierney would also be solid, but I'd rather take a chance on a younger version of him with more upside in Steel if I had the choice. Strome and Rask do not seem like fits for PK, so let's eliminate them out of contention for that spot.
At 2LW, we mostly just need a guy who can play with Nylander and Tavares. I wouldn't trust Heinen on either special teams (which may actually be fine since we have guys like Marner who can do both) but at ES with Nylander and Tavares, he may end up being the best fit. Alternatively, if Strome was willing to buy in, he too would be a very interesting fit for that line. Added bonus, he can win draws and PP, so that means you would only need to find a center who can PK for that open center spot.