Are there opportunities to rank up as a reservist?
Absolutely, and much faster than Active Duty typically.
Does an aspiring reservist have to be active first? If so, how long?
No you do not, you just need to contact the unit and see when tryouts are.
Would you still recommend your Pass the PAST program for Reserves Pararescue?
No, I would recommend doing the Get Selected program for the reserves since you will have to go through their hiring process, which will include a lot of the exercises in the workout.
Is it possible to do PJ or CCT as a reserve?
Yes but you would have to get in touch with a reserve recruiter, then go to that unit to do an assessment and board with them in order to be hired by that unit. Then they will send you to BMT then SW Prep, then A&S.