Counterattack is not counterattack (because naming in this game is stupid af). Counterattack is pride-like buff, the less HP party member has, the bigger assault bonus.
Tower medals does not reset, you can get however many you want from events before using them. In my personal opinion buying bricks (SSR limit breaking items) is the best usage of medals. It gives the most reliable way of getting Kamihime/Dragon Eyes FLB weapons (and some of them are damn strong).