Actually they are not, Hausa people don't carry this variant of DNA J1 subclade
Haplogroup J-M267 - Wikipedia
That is why you have many Sudani(North)(not all) that look like this.
Vs Hausa people.
As far as relationship to Northern Groups, NO. Also, our ancient culture was different from theirs.
Nor did the Hausa practice Christianity at one time. Nile Valley Sudan and Upper Egypt was Christians before the advent of islam, the region was one country.
No, the Hausa do not share our history.
They are most likely related to the people in the Darfur region or South Kordofan. I am not saying they are, but possible.