Ill try and help..

#5 no handguns allowed
#4 best boarder towns seems to change from day to day, a few have a history of being even more corrupt than other Mecican towns, ie TJ.
#3 Photo ID(state ID/ Drivers ID) is plenty as long as you are just visiting a boarder town.
#2 Ive never been able to get Hydro, during several visits to Mexico. I have had shady pharmacias try and sell me fake percocet.
#1 Ketamine Im not sure, Ive never asked about steroids. Worst case senerio you would pay a local doc 10-20 usd for a "office visit".

Drew