Man. A and E are just pulling all manner of OUAT alums.
Which could be an advantage for them, in the event they think about having any of these actors return for OUAT. Even if some of Dead of Summer’s filming schedule aligns with any of OUAT Season 6, that doesn’t rule out the possibility for the following reasons. Both shows are run by the same people, owned by the same parent company, and film in the same area. This makes scheduling actors between two different shows all the more possible. I wouldn’t be surprised if any of the current OUAT actors make guest appearances in Dead of Summer either, provided that they aren’t preoccupied with a given OUAT episode.