Haihai , may i know if the only way to get Miyamoto is with nyankoporon ? Or i can get her after the quests?

You can only get her via Nyankoropon. If you want to get her, you can use SP Gatcha tickets (Which Musashi gives TWO if you complete everything) or Onigiri Coins.

Please note that even if you get SP Gatcha Ticket, its not a guaranteed roll to give you Musashi.

Awki , thankies for the answer :3