Oh Timewalker, that is absolutely wild! I can only imagine one of the GH characters waking up and finding, say, Bobby Ewing in her shower. "All a bad dream, honey."
And I thought the JJ-Trek fans had trouble reconciling universes.
SF "Click Here for the Universe Where Nero Prevents Nash from Ever Meeting Jessica" 3
Identical twin, triplet, or cousin (the last is how they explained Anthony Geary, who played Luke Spencer, coming back after several years to play a different character - he didn't want to play Luke anymore, so TPTB had both him and the actor playing his on-TV son playing their identical cousins instead).
Finding Bobby in the shower wouldn't faze any of these people.
(mind you, that's not what happened with OLTL/GH; they had to make completely new characters for 2 of the actors, and the third one ended up as a recast of an older GH character)