I'm trying to figure out, if it's possible to authenticate via an on-premise ADFS, using OpenID Connect?
I wasn't able to find any examples on that - is this scenario supported? Or should I federate ADFS with AAD?
No, ADFS 1.0/2.0 do not support OpenID Connect.
Update: the newest version of ADFS i.e. ADFS 2016 does.