qantas 62 arrives at 7am. last time i arrived at similar time international customs area was quiet. but australian immigration and quarantine can be a nuisance. i would allos more than 1.5hr

i am not sure if you have OWE but business.class lounge at Brisbane Domestic is.quite nice. i would spend some time there.

transfer is by bus on curbside. the process can take 15- 20min from waiting for bus (if u missed it) to getting off domestic.