Rochelle...I know the BP site your talking about and it's been up and down for a long time.
As for the tank, so far you are ok. But don't add any more. Your BP's are going to start growing fast, especially if you start feeding them blood worms or brine. Not too sure why you have so mony cory's in a 30g tank though...must like them huh. But I think you reached your limits.
Liz...you're right, thes fish can get to be 10" but don't forget, that's not overnight. Plus, because some distributors, prefer to dye their fish to enhance the color, that stunts their growth considerably. Anyone thinking of going into BP's should watch out for these dyed fish. BP's can be aggressive, but mine just like to chase each other around...still have to give them caves and such just in case...lol.
And yes, my avitar is a baby BP before he changed colors.