This right here is to give you guys a starting point to create the story. I would write it myself, but I have little experience writing stories like this, not to mention my inconstant schedule and lack of focus.
Each of our characters will end up in the Bayonetta world through different reasons. To briefly sum them up:
Ruby and Yang would be dragged in whilst looking for Raven.
Blake heads somewhere quiet to try and make sense of what she should do about the White Fang and Adam.
Weiss has had enough of Jacques shit.
Joana's looking for somewhere to train before applying for Beacon.
Pyrrha's trying to figure out what her fate is.
Nora dragging Ren on another adventure, particularly after being reminded of Kuroyuri and needing some quiet time.
What ever the reason, each individual falls into a portal leading directly into Inferno, the haphazardly formed group forming in order to try and survive against multiple demons (Weiss and Joana haven't received Mytrenaster and Crocea Mors, so they just have a simple rapier and sword/shield combo respectively). When they get out, they had crossed dimensions and had landed in Rodin's bar, whilst Cereza and Jeaune are just catching up. The Remnant Witches (this will make sense later) do initially panic, once they calm down and explain what happened to them, the others are just bemused by the situation. Cerezas' had plenty of time travel hijinks, dimensional travel ain't that out there.
Offering the Remnant Witches a temporary place of residence while they figure things out, the gang trades stories about who they are, what they want to do with their lives, basically this segment is where they begin to bond with each other. Of course Rodin has an interesting observation to make. Turns out Ruby and the others had Umbra potential (See lore changes for more details). Before long, things start getting big. One such reveal is when RWBYJNPR get caught up in a battle with Bayonetta and Jeanne against a group of angels and manage to summon a demon from Inferno, showing Umbra Witch potential. The other is when Rodin reveals that in his possession...
is the body of Summer Rose.
Yep, that's a thing that happened. If you remember the lore changes here, things are gonna start getting bigger from here. Now the group have a reason to return to Remnant (Ruby and Yang moreso), they decide to offically train in the ways of the Umbra clan whilst Rodin works on how to open an entryway to Remnant.
A timeskip will be placed at the end to segway into the second arc, for the sake of saving time. Some segments of their time training will be used as interludes (mainly to help showcase how the ships developed).