Match Game, which is currently on ABC, has had a ton of people from SNL (and other NBC shows) over the years. I didn't even know there was an issue with that. Game shows have had stars from different networks appearing on their shows for 40-50 years (more or less).
FWIW, the original Family Feud did feature stars from ABC more often than not (including The Love Boat, All My Children, One Life To Live, General Hospital) instead of shows from CBS & NBC. IIRC, the nighttime syndicated Family Feud aired on my local ABC affiliate at 7:30 right before the ABC primetime specials when they had them. Not much promotion from Dawson, I don't think. Usually the stations would.
I don't think Pat & Vanna will be doing anything in their closing segments right before the show. If there was one, it would be edited in. Not much in the closing segment from one of their regular shows