I drop by to make Hunter hesitate.
If you looking for rainbow hit that have 100% re-act, it's has 2 unit.

Dendrobium
Active do 2.2x dmg to 4 enemy.
Passive
- Increase her own ATK 10%
- Increase ATK to party 22%
- Have double rate to use active skill in first turn
- 100% re-act after 1st attack.
Her speed is 530.

Usagi no Ou / Lagurus
Active do 2.2x dmg to all enemy.
Passive
- Increase ATK to party 15%
- 100% re-act after 1st attack.
- Increase team speed by 150
- Convert 120% of team speed to buff party ATK
Her speed is 750.

You can pass this deal if your wallet not ready.
I think the next rainbow ticket should come in November.
But I think no rainbow deal that cheaper than 5000 DMMpt in the past.
Also on DMM the ticket can trade for both 5* and 6* rarity.