payoo
Being French which is I assume is what you are should make this simple. New job or not BALPA (The big pilots
union at BA) is not finished with BA over who/when/where/how these jets will be crewed.
Good luck with the selection but to be honest you are better off to apply to BA directly as many guys from Europe do and avoid the headache that may arise from your goal of working for this start up.
Trouble is brewing and better off to avoid it if you ask me. I think a a few BA pilots may agree.