Permissions issues with High Sierra

After upgrading to new iMac (27inch, 2017, 3.8 Ghz Intel Core i5, 16GB Ram, 2TB HD) and OS 10.13.3 using Time Machine, the internal drive and all three Thunderbolt to Firewire external drives have become Read Only. One of the externals has Time Machine, one still has Yosemite installed, and the third was simple storage.

The external drives I was able to get to by using Get Info and giving myself Read & Write access.

I installed HS on the third drive, booted from that and corrected the Macintosh HD situation.

However, all the folders and files on these drives are still asking to be authenticated (only once each) and it's taking up a ton of my time. Especially since the "Apply to enclosed items" has no effect.

Any suggestions?