Welcome to FT
You should receive your QF107 BP in Brisbane when checking in.
So, is it going to be a case of re-checking my luggage immediately after I clear immigration and customs at T4 and then walking to TBIT? Or will I have to take my luggage with me and check in again at TBIT? Any info would be greatly appreciated
You will arrive at T4 and clear immigration/customs and redeposit your luggage there. After redepositing you luggage simply Exit T4 onto the footpath, turn left and walk around to TBIT. Then up to departures level and through security screening.
Should your inbound flight be really late and you miss QF107, you will be re-accommodated on an AA flight to JFK from T4.