For a possible trip JFK-CDG, I'm thinking of buying from DL a DL codeshare operated by AF and a DL operated return flight. The AF flight has a higher history than I'd like of being canceled. If it is canceled, do I contact DL about rebooking and which airlines would be available?

The AF flight schedule is much better for me than DL, else I'd do the outbound on DL. This would be in business, if that matters. I once booked these flights through DL vacations, the AF flight was canceled and DL vacations rebooked me on DL (after AF auto-rebooked for the next day), but DL vacation's pricing is not favorable this time.