(Jossed) The Dark Pretty Cure will join the other Pretty Cures.Because, every season needs a Heel-Face Turn.
The season is part of a plan of bringing Ojamajo Doremi back.Because having the same art director as Ojamajo Doremi can't say anything good. Think about it: Tsubomi is the same shade of redhead than Doremi. The main theme of the season is flowers, and that was the theme of Ojamajo Doremi #. Previous seasons were also trying to bring Ojamajo Doremi back, like Fresh Pretty Cure! having (in the start) three cures, pink, yellow/orange and blue, and a magic baby. As of Fall 2011, there are plans for a Ojamajo Doremi light novel revival entitled, "Ojamajo Doremi 16''. It will feature the Ojamajo characters, who are now 16 years old. There are also rumors of an anime series of this light novel, sometime in Spring 2012. And yes, Umakoshi would be the art director.
The little girl holding the Heart Perfume at the end of the final episode......It's not Futaba. We never saw her face, and just because she has the same hairtie it doesn't mean it's the same character (in episode 9's time-passing montage/flashback combo, Tsubomi had several hairties, in the same format, but in different colors). So while she could be related to the Hanasakis, she could probably be a daughter or granddaughter of either Hanasaki sister, or perhaps even a reincarnation of Cure Blossom's Enemy Without from the Super Silhouette mini-arc.
The Opening and Ending Themes are recorded by the in-universe versions of Aya Ikeda and Mayu KudouWhich makes the Theme Tune Cameo in Episode 41 plausible.