1. Unknown, but the dev likely never intended it to happen. This WILL happen in 1980s mode though.
2. Or you could call mercenaries/the military, and have them drop tanks or bombs or whatever thing that's deadly enough on your enemies. Dev said that he doesn't like ranged weapons. Also, this ruins the purpose of the game. AND, mercs are expensive, so she won't be able to fill in the cost. Unless the school is way too suspicious there is no reason for a blackop (which again, Japan's ninjas concept is mostly gone, and their government probably doesn't have the capacity for blackop let alone the need). Speaking of that, a silly yet funny (that the dev will include as a joke, if he ever wanted to have one of these) idea is for Ayano to pick up a tactical targeting device somehow left behind by a weaponized organization and she pushes the button on the co-ords of the stationary rival.
3. Something that the dev will definitely add in the future.
4. Also an upcoming feature and is perhaps the equivalent of getting student rivals expelled.
5. Dev said that he wasn't working on it for some time but he does know a concept. Extends the game over by a little where you might go beserk and kill someone else.