I would think Davis would be the odd-man out.
Ranek is a proven quality and they have him under contract for one more year plus an option.
Keeping the Canadians would be more beneficial. Having 2 tailbacks and 1 tailback/quasi-fullback and one very strong fullback, you could rotate them in and out and have a lot of flexibility in formations.
This would also allow the use of an American somewhere else, most notably on the O-line.
Last game may have a devestating impact on the current status of O-line for next year. Having an added Canadian in the backfield the Cats could possibly go with 3 import O-lineman.
The problem is, with the plethora of lineman in the States, the Cats have been having a lot of trouble finding ones that are suited to the Canadian game.
If the the scouting staff can find some quality talent the running game could be the dominant part of the offence next year.
Seeing an average 150 yards rushing per game next year would not be out of the realm of possibility.