unable to open /var/db/sudo/ts/: Permission denied
That’s a very odd failure. I would probably boot to internet recovery and reinstall the os on top of what you have. If you have a backup, great and if not this isn’t a risky operation and something is certainly messed up with the permissions and sudo failures. 

Unless you have a very good idea why things are specifically broken, perhaps some scripts to change ownership or other sorts of administrative changes that you know were made to that system, it’s probably a lot faster to just get a get operating system and then fix any remaining problems every install doesn’t solve immediately.