Why not use the hammer valve? (That would be #2)
My .02
Ball valve:
Slow opening time no matter what you do.(a matter of opinion)
Spring operation is nearly as complex as the hammer valve.
Hammer valve:
The best option you presented.
The most complex option you presented.
Blow gun:
These have two purposes in the "spudding world", as the main valve in a bbmg, and to pilot a real valve.
It's your gun, you decide.
But ask yourself, "How dedicated am I to the project?", before you start.
The answer will guide you to the right decision.