Originally Posted by Maladaptive

I'm in the same boat as you. Have not enough Knights to completely fill three teams unless I dupe some 2 stars. I can't finish the last mission as not every team is capable of winning against the pests.

Good news is: these maps return once a week, so you can just level up a bit, and try again next week, or the week after that. Flower gems are only rewarded the first time you clear them, so it's not like you will actually miss it, you'll only get it one or two weeks later.
Once we get Bloomed Forms, these maps supposedly become the farming grounds for special items required for blooming, but by that time, your girls are probably strong enough that you only need one or two of your strongest on each squad.