Only problem with uncovered water bowls is that they will throw the food they don't like into the bowl.
That's how we learned that pellets were unacceptable.
Don't over complicate.
Keep them in separate cages EXCEPT when you want more rabbits. Movable wall is just asking them how bad they want to get at each other when you already know the answer to that. They wont leave each other alone and you'll have a new litter about every 31 days. Oh boy...