1: There's a 'user' field for enqueued actions, for instance the a_user variable in the ctst_TURNQUEUE state in obj_battlecontrol's step event. (this state is probably when you want to consume the points, since it's when the action actually happens). This "user" field is a battlemonster object ID so simply check its side variable: if it's equal to side_ENEMY it's an enemy and shouldn't consume points.
2: Correct, enemies just pick a random move this way (add all valid actions to a list, shuffle it, pick the first option). If you want something priority-based you could rework what happens in the bcontrolstate_ACTIONSELECT_ENEMY segment to use a priority queue instead (ds_priority functions), where you insert things and they're automatically sorted so you can pick the highest priority value - it's pretty much analoguous to how ds_lists work and the only hard part is figuring out how to compute the priorities - you might want to add some new fields to the move database for storing base priority and priority increase per turn to make this easier to control on a case-by-case basis, and maybe rework target selection a bit to account for type matchups (i.e., add every possible move-target combination to the list but multiply the regular priority with the type multiplier for that target)
(Also you might want to still add a little bit of randomness to the priorities, so the AI doesn't become completely predictable and the player can exploit it)