Very very nice score! What a way to stock a tank!
As for your questions about the brain ID, just my opinion, but...
In the third batch of shots, and that last shot in the fourth batch - I'd say that's a Symphillia, and not a lobo. Google up some pictures if you don't have a coral book and I think you'll see what I mean. Symphillia is one massive colony that doesn't look separate when it retracts. It looks like from the shots that the "lobes" of yours are not separate. If they were, that would indicate a lobophyllia.
In that last shot, I'm thinking like you... that isn't an Acan. It just doesn't have the right look. (Don't know how to describe it.) I'm thinking some type of blastomussa?
In your second batch of shots, that one brain that your clown is hovering over... I'm pretty sure THAT's a lobophyllia.