Maybe you don't have to employ, BA pay for 2 staff at the gate, there's little for them to do until boarding, when you get down to the last 10-20 people then one person could continue boarding while the other does AAA ect.
In NCL with aviator how many gate staff are normally present ?
Ive heard the BA contract at EDI may go to them, current GHA is on third 30 day notice.