Well, I’d suggest also getting some BCAAs (as much as you can afford w/your supplement budget). In addition, I don’t believe there is anything in HOT-ROX Extreme that will cause you to fail your drug test. You should be safe there (I believe this issue has already been raised and answered, but search around to be safe).
Quite frankly, I think if you clean up your diet and drop junk calories you may be able to do it. There’s a lot of crap in your diet if you’re 24% bf ish, so replacing them with clean calories will drop a little fat without having to cut calories at all.
Immediate advice is to drop any sugary drinks/soda you currently consume, and drop Gatorade outside lifting/practice and immediate post-practice/lifting times. In other words, don’t chug it during the rest of the day. You should be able to replace those calories with good solid food (or at the very least regular old whole milk) and drop (a little) body fat and stimulate muscle growth.
BCAAs will help a lot in gaining muscle, but they require you to be diligent in dosing/timing, and also swallow a lot of pills, so it can get expensive. But in your case, you need to stay anabolic as much as possible, and if you’re not going to use a fat burner, then BCAAs also help you partition nutrients better. They don’t do as good a job though.
They do help with gaining muscle quite a bit however. I’d suggest 6-9 pills in between meals (about 1 hour before you’re supposed to eat again), aiming for about 4-5 doses a day. BCAAs are really good for post workout recovery as well.
Creatine–between 5-10 grams daily will do it. Any time really, but if you want to make extra sure you’re topped off for training/practice, then one serving about 1-1.5 hours before training, and/or one serving after training. Plain creatine monohydrate is all you need, you can make your own carb mix if you want an absorption boost (just drop it in your post training shake).
Buying anything fancy should automatically earn you a pimp slap. You can mostly make those concoctions at home for a lot cheaper than they’ll sell at GNC/online. Monohydrate sells dirt cheap-- Biotest carries the cheapest price I can find.
Get only stuff made with “CreaPure” or “SKW Labs” creatine. That’s the good quality micronized stuff that won’t give you gut distress. Biotest makes some, Optimum Nutrition makes some, other make some.
I’ve never really used glutamine as I don’t really buy the hype, but some people have sworn by it. I’d say probably just pre and post workout, maybe some other times with your BCAAs.
Hope this helps. Gaining 15 lb of true muscle is gonna take a lot of time though. A lot of time. Good luck.