I didn’t see a thread discussing this, but it’s also hard to search for the exact concept.
In FEDS, enemy units who are stationary (mostly bosses) have their mov set to – and their corresponding movement/attack range on the map altered to match. This makes it easier to check enemy attack ranges without having to experimentally figure out whether an enemy’s AI is set to attack in range or to never move at all.
I’m thinking that this is possible to create in FE7 with a routine that checks for AI parameters and then sets movement to 0 or – if the AI parameters are [0x0, 0x3, 0x9, 0x20] or something like that. In cases where you want to CHAI a unit via events to become mobile mid-chapter, you would simply use a different initial stationary AI parameter ([0x0, 0x3, 0x9, 0x0]). It may actually be better to only check for the 4th byte, although I’m not sure what it’s used for other than Guard and GuardTile.
Of course, I have no idea how feasible this is, and it’s ultimately not a high priority mechanic - I just think it’s a neat feature that saves some effort for the player. I’m merely bringing this up to put it on the docket, so to speak. If anyone is interested in investigating it, be my guest.