Both are completely plausible, with the caveat that scholarship is not mentioned once in the script for the ch5 beta, so the theory is built off the oddity that is the steam blurb, coupled with the suggestion that Vic got a (non basketball) scholarship. The first we know of basketball is Nika looking at the tryout poster (I think), then Trey asking him if he's going to go for it. As far as any scholarship goes, we've only got that one image of Vic's letter, and some vaguely suggested content. The mention that Noji thought Nika wanted to go to college, is a different conversation to (for example) 'they offered you a place, you should take the opportunity! Carpe diem!' It's currently very ambiguous but suggestive that there's more at play than it was the only college they could afford.
I have more belief that any scholarship that was for both of them would be discretionary, as Nika hasn't chosen any focus in his studies, and seems to be picking up whatever interests him in college life, rather than the obligitory scholarship activities. The whole basketball arc is the underdogs coming out of nowhere to impress the pros, Nika's currently training with the misfits, and Stahl and Hill know they have an uphill battle to get a team out of them. Also, Zara would know Nika had a scholarship for basketball before he did - she'd sniff it out, just like Rambo.
If there's a scholarship for both, it's due to nepotism in some form, which furthers the mystery aspect. Nami clearly doesn't have the basketball skills to be granted one on sporting merit. The only connections we have are the vague, suggestive wording of the blurb, Vic's mention of a list (that goes against all kinds of privacy issues) and Vic having one. The current script doesn't support anything conclusive, and the blurb only hints towards it.
Regards b) 100% plausible, but impossible to keep secret from Zara.