I would build a "intrinsic motivation" first curriculum, where knowledge is handed as powertools to a already existing passion and the self-thought "expansion" of knowledge is the most important gift to be made.

If the child is fascinated by video games- i would help it make video games, the curriculum be damned. All knowledge holes can be filled later, but the passion to wanting to know, can never be restored unless the want for knowledge remains intact.

No you don't. There is a narrow range of abilities at each level if students are properly held back when they haven't mastered the material.

Their interests are built by what they are taught. "Socioeconomic background" is a tautology. Their backgrounds are irrelevant.