You just called out two wallet that will not give you access to your private key, but you can make use of your 15 word phrase in getting your private key, all you need do is back up your wallet, get the 15 word phrase, download bip39 from github repository, open file in your browser, insert the 15 word mnemonics , scroll down and find the wallet with the fund, you will see the public and private key beside it. That all. Note: coinbase don't give you access to your private key