Looking up my transaction TO heat ICO, I can see that the BTC came from 4 different addresses.

Do I need to verify all of them, or just the first one?

I understand it is not possible to choose a 'from' address when sending BTC from a core client, how do I make sure the 0.00005 BTC actually goes out from the same address you guys sent it to?

Edit: I see how to do the second thing with "Coin Control."