The answer is all of the above

I am running Kerria with 50% debuff and Burning Bush(debuffs enemy skills while buffing mine) getting me the best results. Best I have done is 12190013. Results basically come down to whether Cherry's RB bonus choses Kerria.

What she really needs is as much skill buff as possible and debuff. The girls to do this do not exist yet.

Blooms will take care of that. Potentials are Snowdrop, Lyco (Miko), Bonci, Epidendrum (Swimsuit). Future RG Bianca Tulip and maybe we get promo Aconite.

I am also getting good production from newly bloomed Paederia on a counter team. Seems just a little debuff goes a long way on counter.
Another 5* that's doing very well is Pitahaya.
Looking forward nine events really excited to add http://flowerknight.wikia.com/wiki/Easter_Cactus
alongside Saffron on the counter team. Will enjoy the resurrection beat down.

Alpinia is great too with 65% debuff. I have only enough girls for 60% and she dies late. I need to pick up that new girl Horse Chestnut and 6* Apple(festival) when she comes out soon, in just 3 events.