Who could be the agents aka faction faces be?

That's her cousin Loren, who's friends with Dorian's mother.

As far as we know her uncle is a perfectly nice man, for a guy who spends most of his time with corpses.

First thought I had after finishing reading Eight Little Talons was that it would be hilarious if Zevran ends up being Talon of house Arainai. Highly unlikely to happen but man would it be funny.

The article says Bioware populated the factions with characters who are fleshed out and have different views so we need to have more than just the leaders. There might even be some conflicting ideologies within each faction and we can have an influence on what they end up being like. We know there's a rumored civil war within the Wardens, the First Warden could be on one side and other Wardens could be on the other, I speculated in the Lucanis thread that maybe his personal quest could be tied to the ultimate fate of the Crows and we could have an influence on how they could possibly be restructured, Tevinter could present faction opposition with the Shadow Dragons being more militant while the Lucerni are more diplomatic and we could choose to support one over the other, etc.

For the Grey Wardens I definitely see the First Warden and Ramesh making an appearance. The First Warden is the big cheese and Ramesh is the one who discovered Ghilain'nain's monster factory. We could also get to meet the characters from The Last Flight who discovered the griffon eggs, possibly, or just new characters who care for the griffons.
For the Crows I definitely see Teia, Viago, Caterina and Illario showing up, likely displaying different ideologies for the organization in terms of leadership, while meeting other Crows operatives to get an idea of who feels what about which leader.
For the Shadow Dragons we know the Viper from the short story and for Lucerni we know Dorian and Mae, I feel we need to hear from more people within both of these organizations.
For Veil Jumpers we know mostly only Strife and Irelin outside of Bellara (did the others in The Missing even say anything?), so it would be good to see new characters there.
Lords of Fortune are tricky, Bharv I think decided to retire from the life at the end of his story in Tevinter Nights and Mateo might still be with Genitivi and his pals. The voice speaking during the Rivain portion in the Thedas Calls teaser I'm not sure is a LoF because of what he says ("Glory to the risen gods, that/they come to deliver this world") but, since the Lords of Fortune are mercenaries without much of a cause, some of them could decide to throw their lot in with the 2 freed gods and that could cause a split within their ranks.
For Mourn Watch we know Myrna and Audric have a connection to Emmrich, but there are many other Mortalitassi that we could meet with. Sidony hates them and, as much as I dislike her because she's just unpleasant, she could offer a different perspective on their role in Nevarra.