I really need for Kanban to work with a multiselect field the way Timeline works.
The ability to group/lane by each option in the multiselect field. Then if there is more than one selection then the card appears in each lane of the selections.
I would think that in the split scenario, if a card is selected with options A and B ... then if you grab a card to move it from option A to Option C, it would result in Option B and option C now. If you needed to add a 3rd selection, then you would go into expanded view to edit the selections.
We are using this as a todo/workload board. Anything under a team/persons name indicates it's in progress, and we can see what they are working on and when each are due. In some cases we have a task that needs more than one person working on it, but do not want to create new projects for these scenarios.