From being an abilities mod on a HxH RP forum, i can tell you that there's a clear notion behind this discussion thats being unnoticed:
Many complex abilities use multiple strengths from different hatsu, not just Enhancement or Conjuration. So labeling Knuckle's Hakoware as Emission OR Conjuration is crazy, because he could easily be using a combination of the three to do it (Conj. Emiss. Manip.) but the key to finding what Affinity he has would be to find out how his hatsu works, since it doesnt work at all when away from the user, we could assume it has very little Emission skill, and since he conjures it on someone else, we can assume he has higher than average Conj/Manip skills in order to stick it onto someone, and keep it conjured there. We could assume he's the best at Conjuration by understanding the strengths and weaknesses of his hatsu. Same with Morel,
Gon proves that people can have abilities other than their Affinity, but the rules of Nen tell us that Gon will have a hard time using Manipulation and Conjuration, and will take longer to use effectively. Which is why Biscuit had him work on the his best categories, Enhancement, Emission and Transmutation because he could learn them faster and use them better.
And no, basic techniques ARE NOT Enhancement. Enhancement IS to ENHANCE something and basic techniques is what you do with aura alone. Let me be more clear: You can Enhance a knife to cut trough most things. If you apply your aura to the kinfe, it doesn't mean that will cut trough most things. It could be that it cuts dimension, throws fireballs, open gates, summon something...Am I being clear?
Enhancement and Basic Nen abilities go hand and hand. for example, Enhancement is a purely supportive thing, it makes someone stronger, faster, more durable and can be used on any thing in the body. But the problem is that's all it can do, Enhancement doesnt break someone's face, Enhancing your fist does. So when Enhancers like Gon, or Uvogin, or Palm use Enhancement Hatsu, they take that all that aura they dont need since their body is now stronger, faster and more durable and put it into a Ko or Ken or Ren. Uvogin was a master or Ko and Ken, because his body was so superhuman, he did this:
Natural Strength + Enhanced Strength + Ko = Big Bang Shot
Thats why Gon's Rock is just a Ko strike, because adding all that aura with the above formula makes for one hell of an attack. And adding aura to a blade, that's Shu. Everyone can do it.