actually there is necromancy, it was shown in form of the inferi (when dumbledore & harry went in the cave and traversed this sea with a boat), but they are mindless creatures with no soul or intelligence.
Yes, but it will take a lot of time. They will be Inferi or something along the line, definitely without personalities or much intelligence. And he will not use them as soldiers, more in trap settings, like in the 6. hp book when they traversed the see to get to the horcrux
its because im lost, and my keyboard sets the first ' on the bottom and if I remove it the next ' will be switched to be also on the bottom. so I just let the first ' be ... sry
mc will have to learn the spells the normal way, until he can cast them in a basic way. then they will be added to the system and he will get boons the higher he levels them, (which will be a process of repetitive casting and unique quests), which can normally not be used.
so the system will be something like a force multiplier like a better wand or sth. (but a lot stronger, when leveled up high).
for getting stronger he will rely on the system, since he can become stronger faster with it, but he could get stronger without it too, but slower.