1. Can I use my new Stellar public key with zero balance (i.e. does not exist on the network) for the Lumens giveaway?
2. Will never-used-before old Bitcoin addresses be entitled for the Lumens giveaway?
3. Will using any Bitcoin address to sign the displayed message going to compromise the address' security (like the kind of security compromise that you would get by sending Bitcoins to others, thus revealing the private key to the blockchain)?
4. Can more than 1 Bitcoin address be used to sign for 1 Stellar public key?
2 yes, but if there is no bitcoin on this address, you d'ont earn any xlm
3 there is no interraction (the, no risk) beetween the sign of a message with your key and the security of your btcs
4 yes, of course : all the puclics keys of the bitcoin blockchain (balance different than 0) are valid