It depends on what marker you have, a marker like a 3.5 Excellerator, Tac-5 (any marker of the TAC-5 brand) or a similar marker like these, you can use HPA in.
Spyder Sonix can use any Co2 or HPA tank
Remote coils are built for both, so yes.
Yes, Tm7s can run on HPA tanks.
Yes, just make sure to use a 4500 psi tank.
Yes, it can use any tank with a valve.
you don't really need to DO anything. there are post-game quests, both normal and DQVC, to complete. you can use your new mode of transportation, acquired in quest 039, which is a normal quest to explore new areas of the world. there are also treasure maps that you can explore. have fun.
CO2 or HPA will work fine with it
any Co2 tank and high pressure HPA tanks.
You should use HPA with a Proto SLG.
Yes. unless you use HPA.
No it can only use HPA because the CO2 will mess up the soleinoid and possibly damge your gun