Maybe it would be considered "essential" travel? Players would quarantine for the two weeks, so it is not an absolute travel ban.
As for being a hub city, there would be benefit for the bottom line of the host cities. Players need hotels to stay in, food to eat, etc. so business would get extra traffic. There's a reason Las Vegas is being looked at hard for the NHL hub plan. They would welcome all the hotel traffic of players and possibly their families. I suspect if the CFL is considering a hub city plan then they will want similar criteria that the NHL looked at:
1) Not a coronavirus hotspot - not sure what the current status of every city is, but Calgary, Quebec and BC seemed to be of particular concern, and Toronto being so big the population density would raise concerns. Winnipeg and Regina seem to be handling it well.
2) A stadium with 4 pro-size dressing rooms minimum to handle the extra traffic. I know IG Field has the Bomber locker room, the Bison locker room, a road team locker room, and a room for amateur athletes. Not sure if they have a fourth full locker room. I'm guessing Roger's Centre in Toronto would have the full number given that the Argos and Jays both played there, can't speculate on any other stadiums. But in Toronto's case that leads to issue #3
3) Not sharing the stadium with another tenant is preferable.
4) Readily accessible practice facilities nearby. It has already been pointed out that with IG Field, Pan Am stadium next door, and the indoor soccer complex which could be divided into two or even 4 separate fields, Winnipeg is well suited to handle to traffic flow.
5) Enough hotel space nearby to accommodate the players and be close to the practice sites - with the University being largely shut down, this might be less of a problem with the dorm space available.
6) A field that can handle the wear and tear of multiple games in a week. Given that natural grass is not an issue in any stadium, this should not be a bar to any of the CFL cities.
Other potential issues would be enough space to handle the TV and radio crews for each game, and easy travel between the 2 hub cities. With one TV broadcaster, that would not be an issue, but the league might need to have an in-house radio broadcaster rather than sending a local radio crew for each team. You could do worse than have Bob Irving cover every game on radio, and with Geoff Currier and Kelly Moore you have capable back-ups both with experience calling CFL games. As for the travel, pairs of cities that would work are Toronto-Hamilton, Edmonton-Calgary, Ottawa-Montreal, and at the outer limit Winnipeg-Saskatchewan (if you want to avoid flying altogether). Just some thoughts on the matter.