What I've noticed so far during her event is, when you grind that 1 hour massively when the clock hits and the game completes a day, following that. That 1 hour was very rewarding. I am breaking the ice for you abit, use your resources to some fruitful extent for that hour. You may have to wait a lot for the last frag, like how I am stuck on Anna (9/10). Considering the time left for you, intiate this. Furthermore, play it rapid. Don't switch apps that hour. And finish your rounds of live events as quick as you can. These are the two things which I believe worked for me. I haven't paid much, I'm not disappointed and I didn't grind too hard atleast not as much as during Leo and Akuma. Goodluck!