In the wild Anemones are most likely found on overhangs and crevices so this is quite normal. Again, try to feed it if you can. If the clown's being way too harsh and is not giving the anemone some breathing room, I've got my suggestion a couple of posts back (again emphasizing on taking it with a bucket of salt). Other than that, it seems like a fine spot for an Anemone.
As for your powerheads, can't really know where the exact placement should be but if you take a couple pieces of sting (half an inch separation or so), tie it to a grilling stick (wood?), and just "measure" your flow in different parts of your tank. If you see the string waving, you should be fine.