Hi JDE...I wouldnt be so sure of that now to be honest. BA are not in the habit of "handing over" slots (whatever about route rights) to their franchise partners without a clause to get them back should situations such as a buy out by a competitor take place. They are just far too valuable for that.
Also, as for the rights. You will find that many of these are granted by the relevant governments based on the clout of having a service operated by the likes of BA. Now BA can allow a franchise to operate the route on their behalf but the agreement with the governments you will find will be specifically endorsed to BA so it is up to the individual regulators to decide if they are happy to have that changed to Bmed or BMI as this case may be.
Suppose we will know more in a few months, no point speculating now. Especially when too much emotion seems to be preventing rational thought on the subject!