I've seen something on the Japanese FKG wiki about the possibility of buying the knights outright. Not sure, but either with in game gold or nutaku gold. So if you are going crazy trying to gacha one, you can cough up bux.

what's with the marigold H-scene, i-it's scary. She looks very underaged.
I don't have that many H-scene yet but that one is the one that got my weird attention.