I still have some more research to do for the OIDC article, but in theory, yes. OIDC runs as an identity layer on top of OAuth. The only thing that makes OIDC unique is that there's a widely accepted "scope" that provides standardized ID information, which is bundled into an ID token and sent with the access token. So there's no reason two applications that are built on the same protocol can't communicate.

Good question, I'll include it when I write the next one.