Call it over-identification with a character, but I completely see a lonely Benton Fraser child. Not one who mopes about it constantly, but someone who feels loneliness all the same. Actually, I'm going to repost the comment I left to Aingeal, because I agree with everything I said there and I'm too lazy to go over the same details in different words.
In response to Benton and Smithbauer's childhood friendship as presented in "The Blue Line";
Actually, I always see it as a pocket of time in an otherwise lonely childhood. We know that he moved a lot as a child (hence he's sometimes from the NWT, sometimes from the Yukon). He went to school and in grade four was at least on speaking terms with an older boy called Delmar. We know that at the age of 12 he wanted to learn how to hunt and had a mentor in a much older person, Quinn.
I don't think that Benton was always alone, but I do think that for the most part he probably felt lonely - and that is why that relationship with Smithbauer meant so much to him - because it was one strong friendship with someone his age, in a long childhood of being the odd one out who wanted to live up to a mythical legacy.
As you say, it's even questionable whether Smithbauer even considered him any closer than any of the other kids they played Hockey with. I would argue that he probably encouraged Benton's hero-worship a little bit, and liked him a lot, but didn't consider them quite as close a friend as our boy did.
In my view, there was a short time there where Benton didn't feel lonely. He had someone his age, with similar interests, whom he felt he could rely on. And he relished it. So much so that it sustained him for quite a while in the ensuing years. It motivated him. That when it was gone, he felt pained by its absence.
But before then and after, I very much see him as the outcast. Someone who finds it difficult to create long-term connections with others (fear of leaving them, fear of being left by them in his turn). Someone who learns to deal with the loneliness but also always feels it anyway.
And in all of this time, I see an unequal balance of power in his relationships - he has mentors, not people with whom he also holds sway of authority.
Now, to me, I don't particularly mind if others don't see Benton as being lonely, because yes, he did have these mentors, there were people there around him, he had his grandparents - perhaps he didn't feel lonely at all. We'll never actually know for sure. I'd still argue that he did, even with one of the Rays around, because there are some people who will always feel lonely, because in their mind they are set apart from everyone else, and Benton is definitely of that type. But to say he didn't feel lonely because of being an introvert?! Grargh argh blaugh!
Maybe, hopefully, it's a difference in the definition of feeling lonely. Perhaps others view loneliness only as a condition in which the subject feels deep and unyielding sorrow all hours of the night and day, which brings them into a state of near-catatonia. Or perhaps others see it like I do, that you want to reach out to someone else, but always slightly feel that you can't. That you're always a little bit different. That people will never truly understand you. And even though, hey, you can deal with that, lead your merry life, the thought does linger there.
It's too early in the morning to feel so rantastic.