So in the polish forums some people were asking if we are going to met people from the main TW3 game, someone used this "#TeamTriss#YenHaters", and the answer by theta77 was :"It could be a trap ...But the answer is yes. Yes, we will meet
I wonder which main npcs may visit us.
The addon is playable after the quest "A poet under pressure", which means Geralt has to save Dandelion to start Blood&Wine.
That probably means that Dandelion will play a role/appear in the story of Blood&Wine, though he is at least "free" to visit our vineyard.
Zoltan is "free" as this point and should also be able to visit us.
Yennefer and Triss should be also "free" for a cameo visit.
The big question is Ciri. She is on the isle of mists, so definitely not going to be in the addon if we start it right after the Novigrad main storyline.
But CDP also said that there are some changes depending on how far we are in the main campaign.
My guess would be that Ciri may visit if we play the addon after Bald Mountain/the ending and if she is alive.
I also hope the other Witchers will stop by.
All this cameos (if they happen) are obvious fanservice but considering it's Geralt's(and probably all other characters tied to him) last adventure, I would really love to see them again for a last time. One last big party for Geralt and all his friends in the vineyard would be so f****** awesome