I like this A LOT! Is this a situation where the temporary wall could be used to separate the broody bantams from everyone else, or would they be better off given a separate shelter during this time?
They should be separated from everyone else and from each other. Temporary would work fine. If they're inside something that's already predator proof, then the separators only have to contain chickens--cardboard can work, chicken wire can work (neither of those would keep predators out).