Only cards. Staples dont exist. For created warriors and items i'd follow the "lean into the TCG you and your friends know the best" rule for ruling.
As for the NPC, its important to remember that internalised mechanics don't really work for NPCs cause there isnt really a puzzle to be solved to make them any interesting to do. You can just play whatever card you want after all. As is, I'd probably represent it by there needing to be an "enabler" card (the discard engine) to allow for more powerful effects or additional simple card moves being played. Then to represent having less resource, if you dont want to fumble, I'd represent it with having less simple card moves. You can imagine the tempo sort of being "stealing simple card moves from future turns".
Alternatively, you could have the enabler card litterally create a "Hand Size" counter that gets manipulated as you add or spend counters.