@Aravisian - Thanks for the suggestions. Network hasn't been an issue. BIOS was set to secure boot off, so I turned it on. Didn't make a difference either way. I also had tried moving to the "Main server", but no luck there either.
I went ahead and let it search for the "closest" mirror, and it chose "xmission", and I just went with it. Everything started to update, but still received errors (see screenshot). I then updated one component at a time, and was able to narrow it down to the one that seems to be causing all the trouble - it's "Upgrade Zorin OS" that it hangs on. I would hate to have to wipe and re-load, but it's looking like it might be the only option unless I can get this resolved.
I would really like to use the "pro" version I purchased and see what it's like as well, but just can't get there from here anyway.
