I’m wondering if we can generate an SSL certificate from via Cloudflare that can be used for a VPN. The DNS for the domain is hosted at Cloudflare. If it’s possible, which of the SSL options would work for this between the Edge, Origin and Client certificates? Also, is this possible on the Free plan or would we need to upgrade to do something like this?
That’s not going to be a valid or practical solution. Unless you have an Enterprise agreement with Spectrum, you cannot pass HTTPS VPN traffic through the Cloudflare edge.
Cloudflare is not a general purpose PKI management tool. You will be best served by issuing VPN certificates from your own private CA, possibly from a dedicated intermediate CA, depending on your other certificate needs.
Depending upon your use case, Access from the Zero Trust Network Access product may be a suitable alternative to VPN.