In regards to Stagecoach Manchester Transfers ahead of BEE Network Tranche 3 going live in January:

Despite the large number of buses transferred from Stagecoach Manchester's fleet to other Stagecoach operating companies over recent days expect over 100 more to leave the Manchester fleet over the coming weeks and more to follow in spring 2025.

I would imagine current transfers are off the back of the entry into service of the Alexander Dennis Enviro 400 City's 11882-11930 Alexander Dennis Enviro 400EV's 80087-80121 from going of off the Bustimes.org latest fleet list, I am sure there other models of both batches that have yet to be delivered by ADL. 

The next set of transfer will be following the entry into service the Volvo B7L Single / Double Deckers.

Looking at the Fleet List Alexander Dennis Enviro 400MMC's 10401-10429 will be on the move as non of these carry Bee Network Logo's/Livery, all other E400MMC's in Manchester do.

All Enviro 200's will also be on the move once the BZL's enter service.

I would hazard a guess all the B9TL's will be withdrawn and that the Ex First E300's will be amongst other Buses to transfer out of Manchester in the coming weeks/months ahead.