As the edit implies, it's already solved and there's currently no known tool for generating the wallet's addresses and keys from the "
chain_private_key".
Please read the previous replies first before posting
This was a good hack. But its still a lot complex to be honest.
All you have to do is to
Click, Copy and Paste 
Don't sweat the terms and numbers.
But do not try that with your current funded account's backup, do it if there's no official tool yet, you really need to spend your coins and you lost access to your account.
I bet if there will be a tool for that json file, the first batch will be command line tools that's much more complex for beginners.
If anyone find one, please share it here.
