CJ
I'm sure you will appreciate, your ONLY chance of mainline access rests with the BA (BALPA) Company Council, and the will of the mainline pilot community. Certainly BA would never, under any circumstances, volountarily absorb BACF into mainline. Why would they?
If the fleet replacement is RJ85, (less than 100 seats) 'scope' is no longer a factor. BALPA would have no levers (nor interest?) to insist that BA absorb the pilots of this fleet onto the Master Seniority List. It would therefore become a stand alone airline, with associated low staff costs (salary, T&Cs, scheduling, hotels, etc.)
If A318 is identified as the fleet replacement aircraft, BA BALPA would (I hope??) be on the case immediately! Hopefully with the backing of the entire mainline community. In the event that the EDI pilot base was maintained, I would expect the outcome to be virtually identical to the old Cityflyer situation. In other words, any pilot on the RJ fleet would have protected 'grandfather' rights onto the shiny new fleet, (LHS-LHS!) and could not be displaced by LHR pilots, no matter how senior. (Maybe a 'regional' type pay scale though!)
Of course it is not inevitable that the EDI base would be maintained! It may be that the A318s could be operated simply as part of the much larger LHR Airbus fleet, possibly with dual report LHR/LCY.
In this case, I still think BACF pilots would be absorbed, though I suspect 'grandfather' rights may not be possible?? However, pay protection almost certainly would be available, to anyone wishing to work out of LHR/LGW.
The only grey area left is if the RJ100s are retained. This would be very interesting indeed, as it is quite clearly documented, that in this case, the RJ100 fleet becomes 'by default' a mainline fleet.
If this happens, and you want to be mainline, you better hope for a strong response from the BACC!
In any event, I can't see this operation folding. It now has a 'strategic' value to BA, which Bacon never had, and as such, should even withstand it's management with a well proven track record of incompetence, and shall we say, insincerity!
All the above said in the hope that no 'unforseen circumstance' has a detrimental effect on the new company! (If you know what I mean!)
Hope it all works out.