Touhou Monster TD ~ 幻想乡妖怪塔防

You can get this by doing Level 14 Moriya Shrine 4 times, just spam 5* cirno. Alternatively level 15 Wind God's Lake Challenge Mode has nothing but Suwako, but it's much harder to beat with Cirno than 14.

I got this by rerolling a tower to a special christmas character, you can get this by just spamming rerolls from gacha boxes and getting lucky

It seems you need to get another gacha box from a gacha box twice in a row, basically just spam gacha boxes