[JumpCrisscross]

> could it actually be reasonable to have, say, sealed containers of fuel/oxidizer of whatever type inside the missile and you "pull the pin" to uncap them and start mixing in the ignition chamber?

No. The economics really shine if you can mass produce dry engines and then fuel them on site, ideally with locally sourced or even on-based manufactured oxidizer (if you’re going LOX).

Barring that, though, not being limited by AP would make the last comment’s hydrazine path acceptable.