Perhaps, but not as much as he might have, had Harry been an ordinary apprentice. Also considering Eb's juice as a wizard? His duels with Harry may have been like Harry teaching
Molly defense with snow balls. The Council was afraid of Harry as a sixteen year old, to keep
him alive, Eb would have done his best to limit his grand son, and he did. I still argue he didn't teach Harry a whole lot of new magic. It still doesn't answer the question as to why Eb didn't insist that Harry return to high school and finish his education, even if it amounted only to formal Latin class and shop, both would have helped him.
Yeah, I don't disagree he might have taught Harry more in a "standard" apprenticeship. But then again, part of it was also to do with the fact that Eb felt he was too harsh on Margaret and so perhaps not. And of course, I am not saying Eb went full out when he did practice duels with Harry. Harry didn't even really know how powerful Eb was until at least when Eb tells him about some of the disasters he caused. Let alone what he saw in Changes and even Battle Ground. If he had duelled Eb for real, he would have died even without Eb's licence to kill. But what you're saying doesn't actually prove that Eb didn't teach Harry magic, or deliberately limited his knowledge (whatever the reason). I think that Harry had been through enough without trying to force him to finish high school with limited benefits, apart from perhaps trying to teach him to see things through, and perhaps also try and socialise him and keep things as 'normal' as possible. I doubt it would have made a real difference. Besides, I think it was as much for Eb's protection as Harry's. With Harry out in the open they were both vulnerable.
Ebenezer had only one goal, to keep Haar alive and for that he needed to change is nature, to make him internalise the laws of magic. To make him not just not breaking the laws but make it impossible to do so. Him being the blackstaf did not help.
Not sure it was just one goal as such, but certainly there was at least a central goal. But I do agree by and large with the idea. I think that whatever Harry is, and whatever Harry is being shaped into, Eb is both aware of it (and perhaps not all of it is to do with being a starborn, although that seems to be the main bit) and was trying to make sure Harry had the choice not to become whatever everyone is trying to make him. To make sure he understood that no one could force him to do anything he didn't want to do. To that extent, I'd say he succeeded.
Yup, which also meant that he nixed teaching Harry any new magic that might make him seen as even a greater threat to the Council. Big clue, he wasn't allowed into the teleport section of the library at headquarters/
Well...I think the Council have bigger worries than whether Harry knew how to do advanced Thaumaturgy etc. Especially concerning Harry. Harry wasn't allowed in the 'forbidden section' because the Council is pretty serious about things being forbidden, and Harry is both some young punk troublemaker (to them) and not a well-respected researcher...who might be allowed such knowledge for purely academic purposes. You get more flies with honey etc. Wouldn't surprise me to learn Margaret Le Fay, Justin etc. had been in there. Probably any and all of the Senior Council (past and present).