Way to just bluntly dismiss the theory out-of-hand.
I know it hasn't been directly declared, but I think there have been some hints that it might have been possible (I'd list them, except I think you'd just bluntly dismiss those out-of-hand too, so I'm not going to bother typing it out), and I'm not going to rule it out as a possibility until it has been directly disproven.
EDIT: Actually, you know what? I wanted to address this.
a) Cole never truly loses his ability to hear people's thoughts or emotions, it just becomes fainter and weaker.
b ) Well, there you go. Maybe Cole's situation somewhat mirrors the ancient elves'?
Cole has strong empathic/telepathic abilities, but it weakens as he becomes more human. Ancient elves were "intrinsically tied to the Fade" not completely unlike spirits until the Veil went up and they were cut off from the Fade and became more "human-like" (started aging, dying, could be non-mages, lost their "conscious connection to the Fade" - Solas's words), etc. Maybe before the Veil, back when ancient elves were still more spirit-like before they lost their connection to the Fade and became more human-like, they could have had minor telepatic/empathic abilities until they lost it much like how spirit-like Cole can strongly hear/sense people's thoughts/emotions but then loses the ability when he becomes more spirit-like.
And if memory serves, Cole never truly loses his ab
You yours
For starters, please de-format because it's really hard to read your text without highlighting it! (Not trying to pick a fight, and wasn't earlier either. But it hurts my eyes trying to read formatted text... I'm using the dark format and you're apparently using the default white format.)
You just pointed out that Cole's ability fades over time. It probably will go away entirely someday, although Cole is an empathetic creature by nature. He's compassion. He will always care and probably he'll always be good at reading people even if he can't feel out what's making them upset. But it's also true that, as I pointed out, he only seems to hear you if you need compassion. If you are hurting, or angry, or etc. he'll notice. If you were perfectly happy, he would not know it because you don't need compassion. That seems to be true of most spirits--they can get into your head, but only if there's something there for them to get. A desire demon can figure out what you want. A rage demon can prey upon your anger. Vengeance knows when you want a come-uppance. Pride knows all too well every little thing you think makes you "the best." If they hear other things, they seem to be pretty good at ignoring them.
It's also very much the case that, even in Solas's opinion, Cole is unique. There may have been spirits, or elves, like him in the past, but I don't think Solas is lying when he calls Cole unique. And if Cole is unique, that means there's no other spirit like him, nor has there been in Solas's extensive experience. It's pretty clear that spirits turned into elves and elves might have been able to return to being spirits prior to the Veil, but even among those, Cole is somehow unique. We don't know how or why or if the only reason he's particularly special is because of the time and place he appeared in, or because he chose a human rather than elven form.
If ancient elves had a similar ability, it'd work similarly. They couldn't just immediately know one another's sexual preference etc. without some other indication, because they would only know thoughts/emotions pertaining to their spirit. Freedom would only know the thoughts and emotions of those who aren't free, or those who are enjoying freedom. Compassion only knows when people are hurting, or helping others who are hurting. Joy would only know when you're joyful or in need of a good dose of happiness. And so forth and so on.
So even if what you're suggesting is the case (my personal opinion is that it isn't, but hey, I could be wrong), the ability would be limited. You can argue that elves are more complicated than just spirits, but the further away from spirits you get, the closer you get to human. The complexity of your own thoughts might keep you from hearing those of others. I'm not sure how it's supposed to work. Even plain old "spirits" can be complicated, as we've seen. A spirit of wisdom can still feel love and become friends. They aren't limited to only feeling the emotions or ideals that they represent, but yet they can only sense those ideas or emotions or the lack thereof in others. And Solas seems to think that spirits should embody emotions, not work through them.
It's complicated. There probably were signs about what was going on in a person's mind if only because the Fade and the waking world were connected, but that would have less to do with "elves" and more to do with how the reality of Thedas was at that point. Spirits were as common as grass, Solas tells us--and spirits reflect people's emotional states. So while I don't think elves were mind-readers, and I do think you'd actually need to talk to a potential partner before finding out their sexual preferences (if they had such preferences--maybe older, more spirit-like elves didn't? We don't know.), I guess it'd be pretty easy to know if someone--even a human--were happy, angry, or stressed out based on how the spirits around them were reacting and what kind of spirits were hanging out in the area.
... Which now that I think of it, would make the Game in Orlais ridiculously difficult. Everyone might not know what you were thinking, but they'd definitely know how you felt about it when angry little wisps started floating around you.
Okay I'm getting tired and not able to focus on one topic at a time...
Long post short, just because I disagree with you doesn't mean you couldn't be right anyway. I just see things differently than you do, and interpret the available info in different ways. I don't come here to argue, although I'll happily debate with you if I disagree, as long as things stay civil. Discussions about lore are a large part of what makes this thread interesting for me.