A few items have surfaced regarding General Hospital's 50th Anniversary. Many of these are subject to change as not everything has been developed yet.
The Nurses' Ball will take place during the anniversary week. We already know it's coming.
Lucy's gowns will come off. This is inevitable.
Possible returns but not definite by any means: Jackie Zeman (Bobbie), Rachel Ames (Audrey Hardy), Stuart Damon (Alan),
Lindze Letherman (Georgie Jones), Jack Wagner (Frisco), Denise Alexander (Lesley), Tyler Christopher (Nikolas), Jonathan Jackson (Lucky), and Genie Francis (Laura). Kin Shriner is a possibility.
Laura will have a story arc that affects her family so the producers will try to bring back Lucky and Nikolas.
If Ethan returns, the role will possibly be recast.
There will be something involving the vampires, but not an actual storyline.
Sabrina will get a makeover, as has been reported.
No Jason recast at the present time.
The One Life to Live imports: No answers as of yet whether they will go back to OLTL temporarily or permanently, or what is going to happen.
Many of the returns depend upon the actors' schedules. Also, it's a question of timing, so that the characters are involved in the appropriate plots.
The Powers That Be at GH will probably talk to all of these actors, or have talked with them, but it's an open question as to what actors will return.