The detox kits don't work THC stays in the fat cells till the fat cells are burned and recycled every 30 days or so.
Subbing is going to be your best bet. The QF should still be fine as long as it hasn't been left in the sun.
They should be testing ph level and creatine levels. But there are some crappy fly by night labs out there.
You won't be watched.
It costs way too much for a company to do dna checking.