I'd like to contribute
Neutrals
-Cyprian Wiley's lines are from TW3 quest ''Get Junior''
Nilfgaard
-Alba Pikeman has ''Aen Ard Nilfgaard'' line that is not written here
Scoia'tael
-Vrihedd Officers lines are from TW2 Scoia'tael NPC
-Ele'yas' lines are from TW2 quest ''With Flickering Heart''
-Ida Emean's lines ''Why have you summoned me?'' and ''The Time of the White Frost and White Light is nigh...'' are from TW3 quset ''Ugly Baby''
-Malena's lines are from TW2 quest ''Malena''
-Iorveth's lines are from TW2 quest ''The Assassins of Kings''
-Saskia's pre-patch lines are from TW2 quest ''Vergen Besieged''
Skeliige
-Priestess of Freya's, Clan Tordarroch Armoursmith's and Clan Brokvar Archer's lines are from TW3 Skellige NPC's
Northern Realms
-Henselt's line ''You want peace? Fight for it'' is from TW2 quest ''Prelude to War: Aedirn''
-Henselt's other two lines are from TW2 quests ''Vergen Besieged'' and ''The Siege of Vergen''
-Dun Banner Heavy Cavalry's lines are from TW2 Kaedweni Soldier NPC's
-Prince Stennis' line ''Peace is Priceless'' if from TW2 quest ''Prelude to War: Aedirn'' not ''Royal Blood''
Glad to be of help. Also please point out the mistakes I've made.