Well, after the ridiculous local aquarium society waved some bags of fish under my nose last night for absolutely filthily cheap prices, I have added to the sorority/community. I had to free up Circe's tank for the crystal red shrimp I bought, and added her to the big tank along with 6 Endlers (2 males, 4 females) and 3 cories (a bronze, an albino and a peppered - not ideal but that's how they were sold, in a big group, and they needed me!).
Everyone is apparently getting on fine. No one is bothering Circe and the cories are shoaling loosely (the two pandas are inseperable). The ember tetras have adopted the Endler's. It's all very cute.