Maybe one way to show field notes during battle is to have a little box with an input option come up like mega evolution has in the fight menu. Another way is to have it pop up in the menu where you choose fight/bag/pkmn/run. Having it pop up like mega evolution would be easier but with the drawback of taking up more of the screen. The graphics could be edited but hard to picture it looking good with a prompt like that. Though I imagine you can call the the function that would bring up the field effect menu during battle.
