you can't get the pokemon off of pokemon black on diamond, but you can do it the other way around.
Migrate from Pokemon Sapphire to Diamond then Diamond to Black/White
Dawn never was on pokemon black and white she was only on pokemon diamond and pearl.
The Explorer Kit is from Diamond, Pearl and Platinum. It is not in Pokemon Black or White.
In Diamond, you can only get Palkia by trading it from Pearl, Platinum, White, Black, Black 2 and White 2.
You can not catch any of them in black or white, but I think that you can catch all 3 in diamond.
you are unable to send any items from the past games to pokemon black/ white
Yes.
if you are asking if you transfer Pokemon from HG/SS/Platinum/Pearl/Diamond to Pokemon black and white will they be gone from HG/SS/Platinum/Pearl/Diamond then the answer is yes.
You can only find a Magma Stone in Pokemon Black 2, White 2, Pokemon Diamond, Pearl, and Platinum. It is not available in Pokemon Black and White.
Pokemon Platinum, diamond and pearl. and black and white 5
You can't trade Pokemon olny put Pokemon in Pokemon white and black's pal park and you can't return it back.
No you can't trade with black to diamond but you can trade from diamond to black using the poketransfer lab. (you will have to have beaten the game before you can use the poketransfer lab). Hope I helped this is luke127 signing off.