1. It's only a monthly thing if I'm not mistaken. I've only played for 30 or so days, so I have yet to find out.

2. From what I read around here, this is the best gacha that makes use of flower gems, simply because of the guaranteed 5*. Guaranteed 6* gacha is definitely better overall, but that costs 5000 Nutaku Gold ($50).

3. I think you meant Justicia. (Oxalis was from the last event; I got her) There's no guarantee in the priority gacha. Those increased rates won't matter if you don't hit the 6% chance to get a 5* in the first place. You can still end up without a 5* at all.

Ticket gachas are way better.