aries85, from my limited, two-years‘ experience as a reservist, I can say that everybody must do the same initial training, depending on the occupation they choose.
Once you have completed the minimum, and have earned your Private‘s hooks, you can take course as they are offered to you, when available.
Certain courses will have prerequisites, some will not.
I am told you can take Basic Parachute after completing your occupation (MOC) course. But forget about pathfinder until you‘ve done other courses and put time in.
Just an observation -- "recce" seems pretty accessible in the reserves. My unit has a recce platoon, with several newbies that finished their MOC on the same course as me. For whatever reason, they are being set up to do a recce course in the summer, and have been doing a comms course on weekends lately (apparently you need comms in order to do recce). Good for them. I don‘t think it will speed up promotion to Cpl, but they‘re keeners and they‘ll do well.
Although I‘ve heard that some res units have a sniper tasking, I don‘t actually know of any qualified snipers in the reserves.
I think it was the Lorne Scots that brought out their C3 rifle to Ex Stalwart Guardian last summer, and I was mincing around and got to look at it, but I have no idea how a reservist gets on a sniper course. That‘s one I‘m pretty sure you need at least to be recce qualified before you can take it.