Baggers and others.
My understanding is that if the Unite membership accept this deal, it will be applied to all staff. The caveat is those non-union staff who signed the earlier offer in June. If the latest deal is better than the deal they signed, they get the new deal. If the deal they signed is better, they can stay on that. All the staff who either didn't sign the June deal or left the union after the deadline will get the deal on offer assuming that the Unite members accept it.
If the Unite members reject the deal, BA may then offer it to the now non-union members who didn't sign the previous deal, but it is not guaranteed.