Yeavinn`s fate and or whereabouts are still unknown at this point . If you play Iorveth`s side in Witcher 2 at one point in Vergen you have an opportunity to talk with Iorveth and he says one line concerning Yaevinn . Somehow I don`t expect Yeavinn to play any role in Witcher 3 other than maybe a passing line or two from people that may have knowledge about him . It would be great if he did make a cameo in some way but i`m not expecting it .
See, that's what I thought as well. I want to play through the games one more time before The Wild Hunt, but I'm unsure of what side to pick because I want to see returning character in the form of an ally. Don't want to start an argument, but I don't believe in neutral. IMO it always leads to things getting worse instead of picking a side in which you believe is the lesser evil. So the question I am presenting is, is it more likely for Yeavinn or Siegfried to me in TW3?
The Knights of the Flaming Rose will most likely join the fight against Nilfgaard, though if you will be able to see Siegfried personally or not remains to be seen.
The Scoia'tael will most likely avoid the conflict alltogether or prey on both sides of the conflict like bandits (seeing that Nilfgaard betrayed them in the outcome of the previous war, so they are hunted by all humans at this point).
But I would not count on actually seeing Siegfried or Yaevinn in Witcher 3, maybe some references to them here and there from people in taverns talking about them and what they did during the war, but I wouldn't get my hopes that high, I would rather say that you will most likely get to see Roche or Iorveth instead.