Since I didn't really have any specific flower knight I wanted to get, I just set my goal to "3 new rainbows".
Man, that took a while...
I had pulled 3 rainbows at once multiple times (never 4 sadly), but there was always a dupe among them.
After a few hours of rolls I finally achieved my goal:



Although the rainbows that appeared during my rerolls would be interesting to have (BB, Choco Lily, Meco, Azalea, Lantana... - the ones I already have alternate forms of), I'll be sticking with these. The new gold is a cherry on top.