Hello Jeff. This is Mark, one of the answer tech from Microsoft. The one that you've talked about the backing up of OneDrive files.
As you mentioned that you already back up the OneDrive folder but you're just thinking not to redownload it after reinstall the Windows 8.1.
What I can recommend you is to just logged in your OneDrive account then the files from OneDrive cloud will automatically sync on your computer. I know that it will take a while but that's is the best way. So that, you may not experience any issue just like what you said that it messed up.
If you have any questions or any concern, just feel free to contact us back and we will be happy to assist you.
This is your reference number for this session: 1291026485
Thanks again for choosing Answer Desk. We're here if you need us.
The Microsoft Answer Desk team