Someone find a way to turn Doug Gilmour's clock back to his prime and give him the captaincy. Since that isn't happening, if this team has a bad ending to the season giving someone else the "C" may actually help (compared to making "impact" trades which, at the very least, are not easy to do).
My first choice would be Muzzin, but regardless, I'd have Keefe sit down with guys like him and Reilly and ask bluntly if they are capable and willing to kick some arse in the locker room. If they care more about being buddies with everyone on the team versus winning. If they are willing to go out in front of the media and not resort to stoic, unemotional, manufactured, lame answers like "we just have to be better" nonsense.
If that guy exists in the locker room, give him the "C" and the backing of a few others (oh please re-sign Clifford) so he's not vilified by his teammates.