Why do you use multiple wallet, did you cheat at bounty or airdrop project, you can use your one wallet for transferring your bitcoin to other exchange account with less fee, never use multi account for joining at bounty or airdrop project because is not good ideas.
No, I'm not cheating. I've used diff wallets like electrum, Bitcoin-wallet..etc and am planning to "move" them all to a brand-new hardware wallet
But why were you doing that?
You could just go along with importing private keys without actually moving your coins anywhere. After you are done, you can then collect all your coins in one address (if this is what you are looking for, of course). Since you seem to care about fees so much, it looks like you don't have a lot of bitcoins, then why all the fuss really? It just doesn't look like a very smart idea to shuffle your coins around