It’s not the best, but you can group the other player characters with your character so they just follow you around the same way the origin characters do. You still lose the slot, but it’s otherwise the same as using an origin character.
My wife left early last night while we were playing and her character ended up coming in clutch in many combats. Figuring out I could get her to follow me was a game changer
I like having both 2D and 3D Mario games. I kind of fell off the 2D games for a while because I wasn’t enjoying the New Super Mario Bros Series of games. I’m optimistic that this will be more enjoyable