How much fat you lose depends on your diet and training program. GW will just push you further than you can get naturally but is by no means going to do the bulk of the work. 20mg per day is plenty too.
Creatine is super easy to take man. Just dose 5g per day indefinitely. I wouldn't bother with BCAA. You get plenty if you are eating a diet rich in protein.
Some of us are just more or less sensitive to estrogen. You definitely don't want to crash it though. It can crush your libido on top of the joint issues you were having. Glad to hear you are already feeling better.