I'm on Percocet, and neither of the two HRT doctors I've had, nor my family doctor were particularly bothered. So opiates seem okay, and I haven't noticed any difference in effect.
I also wasn't warned against alcohol, so I'm not sure where you got that from. The painkillers come with big orange "NO ALCOHOL, IDIOT" stickers on them, and none of the HRT drugs I'm taking or have taken had them: estradiol acetate, estradiol valerate, prometrium, spironolactone, androcur. Drinking has pretty much the same effect on me it always did.
No idea about weed or mushrooms. But even if I did, I'm not allowed to answer here due to the TOS for Susan's Place. Speaking of, I'd just like to point out that the Percocet is legally prescribed - please don't hurt me, mods.