Ok, so I should move all of them to 1 myetherwallet account.
My other questions then are:
Can I transfer the 3 I have left on the exchanges, DENT, Digibyte, and Bytecoin even though I don't see the coin as an option in myetherwallet.  

And 2, will it cost me to transfer them from the other wallets to the single wallet.

All help is greatly appreciated.  I can learn so much from educated users on the forum quicker than finding out the hard way, like making costly mistakes.