Joining the BA master seniority list does not mean merging with it. These days, during company mergers (something which I highly doubt is on the cards with BACF), the law requires that as far as possible, no worker in either company is unfairly disadvantaged. BACF pilots obtaining long haul command positions ahead of current BA pilots would be a massive disadvantage to the BA pilots and a massive advantage to BACF pilots, and so it just isn’t going to happen. The law would not allow it.