I created a wallet on a USB and one with coinbase. I bought a bunch of bitcoin on coinbase and transferred .01 bitcoin to my USB wallet to make sure I transferred it right before I transfer everything and lose it all. Than I transferred .04 bitcoin. The next day I transferred .01 and than .04 again, because of buying limits while my bank account autherizes. I checked the balance each time on blockchain.info and the money was all going in there just right. I than was getting paranoid being new to this that I set up my USB wallet wrong and decided to plug it in to make sure I wasn't throwing my money away. I plugged it in and it had the funds. I wanted to do another test and transferred .01, than .05 to my coinbase wallet. the .01 went and the .05 went but I lost .04 after transferring the .05 . I understand that transferring can have fees and am wondering if that .04 lost is all in fees? Would the fees for all the transfers be taken out at the same time? I listed every transfer I had done up to that point in this and am curious if .04 is normal for fees for that many transfers. Also, while on blockchain.info I see the addresses I have sent bitcoin to, but their are usually 2 addresses, one says "spent" and the other "unspent", or both will sometimes say unspent. I recognize one of the addresses usually but not the other one. Is the unrecognized address the address of the miner who performed the transaction and the number next to it the fee? Finally, is my offline wallet now compromised and at risk of someone having the keys to it? Should I keep using it and not plug it in anymore, or should I create an entirely new USB wallet? thanks!
Transaction fees occur for each individual transaction and .04 btc is far too large for one transaction fee. You should open a ticket with Coinbase in order to receive an answer that will not sacrifice your privacy (by linking your transaction ID here).
Look up "change addresses" to understand why you are seeing multiple destination addresses for each transaction.
You offline wallet will remain safe unless you expose your private keys to the internet.