Still can't find the answer to this one. Crux of the error is:
2020-11-18 19:06:51,914 DEBG 'start-script' stderr output:
Unable to parse IP address: `'
Configuration parsing error
2020-11-18 19:06:51,916 DEBG 'start-script' stderr output:
[#] ip link delete dev wg0
2020-11-18 19:06:51,962 DEBG 'start-script' stdout output:
[warn] WireGuard interface failed to come 'up', exit code is '1'
Full log is attached in an above post.