So, would you include him in your list of top PGs? Or SGs? Or Combo-guards? All the above?
I somewhat made this distinction in my previous post, and I've written a lot about the modern day positions in the NBA, but I'll try to answer your question as directly as possible.
Kyrie, Wade, Lillard, Harden, Steph, and guys like them are combo guards. They aren't traditional point guards, nor are they traditional shooting guards.
Traditionally shooting guards don't initiate the offense of a team, and they aren't one of the primary ball-handlers in an offense. Plays, traditionally would run through the point and post before landing in the hands of a shooting guard.
But in the perimeter-oriented modern era of the NBA, that's changed drastically.
Guys like Allen Iverson can't be classified as either a point guard or a shooting guard because he plays both positions and plays them both well (as you yourself stated about Tim Duncan). So Allen Iverson is a "combo-guard."
Kobe on the other hand is not, he's a shooting guard, because historically, he tended not to create for others; likely by choice, because he's demonstrated the ability to do so.
Joe Johnson, Jimmy Butler, Klay Thompson - these are examples of wing players who traditionally play the off-guard role on their teams because of their skillset.
So, not to divert from the point. Kyrie is a point guard because that's the position he plays on the starting roster for the Cleveland Cavaliers. It isn't to say he couldn't play shooting guard, and he often effectively has.
So for comparative reasons, I think it makes no sense to compare Kyrie to someone like Joe Johnson who would only be effective (as would the entire team) if there was a point player on the floor. This is true more for some than others.
James Harden isn't the best person to play point given their roster. There are other, better defenders and facilitators than Harden at that position already on their roster; so playing him at the 1 is only really advantageous if (1) the opposing team is post-oriented and not perimeter oriented, and (2) you're trying to go big.
Since both of these conditions are rarely met in competitive play, Harden is mostly going to be played at the 2 - or SG position, even though yes he is a combo guard and capable of playing the point.
With that said, to answer your questions:
So, would you include him (Harden) in your list of top PGs?
No. He plays shooting guard for the Rockets. But I would include him on a list of all guards or combo guards.
Or SGs?
Yes, that's his starting position, and since the NBA still uses the positional system it makes sense to categorize him this way for comparative purposes. But, there is a limit to how far this label really applies to him. He's really not a traditional shooting guard, by any stretch of the imagination.
Or Combo-guards?
Yes. This is the most accurate description of James Harden.
All the above?
No. Harden plays the off-guard role for the Rockets, and even though he's a combo-guard, that doesn't qualify him as playing the point guard position for his team. Someone else is generally taking up minutes in that role for reasons likely pertaining to facilitation and defense.
If however Harden were moved to the point by the Rockets, because say they acquired Jimmy Butler and wanted to play him at the 2, then yes, I'd put him on the list of point guards and combo guards and remove him from the list of shooting guards.
Personally, I'd just call him a ball dominant SG and leave it at that.
I think a lot is missed in this description, but that's your prerogative.
Personally, I don't really care about a 4 year old comment you made about Kyrie - worse things have been said about the kid in that time, that's for damn sure.
But I think in an effort to defend that stance you might be missing something special in Kyrie. This guy has MVP potential and I'm not sure if you're seeing that.