Happy belated birthday, Lola! 
Personally I think Dorian is out. Remember DG didn't seem to remember/know who Dorian was. Of course he could've been faking, but I'm not sure. I think Solas or Vivienne replaced him, and hopefully we'll get an unknown (as of yet) third female mage. (Though I'd prefer female rogue)
I think Dorian is either totally out, significantly altered, or has been combined with another character. We haven't seen anything that could be conclusively identified as Dorian since the survey leak, and he hasn't made sense to me as a character for this game ever since we heard the announcement that we won't be visiting Tevinter. A character with heavily Tevinter-focused goals seems like a strange fit for a game where those goals couldn't be directly addressed in his story arc.
I see Dorian more as a character who would maybe fit better in DA4 (assuming there is one) than in Inquisition.
But anyways, I hope there is no more tragedy for Cullen. Poor man has gone through so much already.
I want Cullen to have some obstacles to overcome, but I don't want his storyline to be a ridiculous tragedy-fest either. I'd like to see Cullen have some problems, work them out, and have at least the possibility of a happy ending.
In general I like characters to have to work for their happy endings, and it's no different with Cullen, but I don't want his arc to be just a total downer from start to finish.
IF Cullen is a party member.
IF the Warden will make a cameo.
What will happen if in romance with Cullen and The Warden was F!Magi Origin?
How will that go down?
I think they would greet each other a little awkwardly, make small talk, then go their separate ways honestly.
There's so much water under the bridge for both of them that I just can't see it being angst-filled or overly emotional. Life has moved on for both of them. I think their feelings have moved on, too, and they could just be cordial and not make a big fuss.
Re: Super Angsty Childhood Revelations!
My Opinion: Please, no? I mean, all well and good if something like that popped up, but I think Cullen's had quite a lot of horror in his life to overcome already and possibly more to come what with the fallout of Meredith/Kirkwall/VEIL TEARS (*dun.dun.DUN.*)... I kinda like to think he had at least a decent childhood. Starry eyed youth and what all. Regardless, I'm definitely interested to see whatever it is the writers have in store!
Yeah, I really hope they don't go there with the childhood angst.
I feel like with the trauma Cullen has been through in his adult life (and the fact that he'll probably go through more in Inquisition,) there's more than enough material for character development. At this point more angst seems kind of unnecessary.
There comes a point where just piling more traumatic events on a character without dealing with their aftermath just becomes cheap. Dumping a tragic childhood on him also could definitely come close to that line for me.