I totally agree with "if you do not know something is out there, how do you find it" and hence some form of education and so teachers will be needed. Also, ethics and moralities are something that might not be as simple as just an upload and so parents/teachers will be needed to teach these in the conventional way.
I don't know about how much the brain can handle. Apparently there are trillions of neurons, so I assume the capacity there is really huge.
I do not agree with "People equate knowledge and skill to ability, but that is not the real case". The definition of 'skill' is ... "the ability to do something". So, looking at your example, let's say if such a technology is developed some day, then we will not only be able to 'learn to use a pencil' but we will also learn to 'do an artistic rendering of a scene in nature'. Let's take the example of the Matrix movie. Neo already knew how to use his hands and legs, but when the martial arts skill was uploaded, he was able to use those hands and legs in a way that an expert martial artist does.
I think that in the future world, there will be a market place of skills, just like how there are marketplaces for smartphones, and we could simply choose what skills we want, pay for it, and have it uploaded. Of course, we wouldn't want those skills available on the market that can potentially make a person harmful to the society.
I love your thoughts on this. They made me think deeper. :))