Alright, so I found out how to fix the first error. I was poking around the directories the error above gave, and I found that missing file in the folder directly above where VS was looking for it. I copied it to the correct folder and the project successfully built and ran.
However, it still gives the expired certificate warning (which doesn’t prevent compile).
A new, not-expired certificate can be generated by you for local testing.
Right-click the project and go to Properties.
Go to Application > Package Manifest…
Click Packaging at the top
Click the ‘Choose Certificate…’ button
Use the dropdown of ‘Configure Certificate’ and choose the Create option.
Fill in a username and password.
It should create a .pfx that is recent that you can build to and no longer see the error.
The certificate will eventually be swapped out with one you generate from the Windows Store once you go to sign it for actual distribution.