I think it is really negative to move after 3 weeks without any guarantee to pass your rating or that your contract is continued after your trial.
I think thatīs a real big problem.
Very fair point!
Just do what most do and what LBR & HURZ also stated: get a crash pad near LUX together with some colleagues to make it affordable and keep the company happy. You need something anyway for before and after a long haul flight. After the (excessively long IMHO)
one year trial period you can always decide if you really want to move your family to LUX permanently.
Good luck!