How does this resolve if some aspects are found to be unconstitutional but others are not?

The rules are intended to cover that case. If 6 justices find that section blorb is unconstitutional then the bracket the market resolves to will be at least 6.

@zax You didn't answer the question as I understand it. For example, what if 7 justices rule the order is wholly unconstitutional, and 2 justices rule that the constitution provides birthright citizenship to children of legal permanent residents but not the children of people here illegally. All nine justices would have ruled that part of the order is unconsitutional, but only 7 would have that the whole order is unconsitutional.

I'm not sure what the confusion would be. The order either is or is not constitutional (even just in part). If 9 vote that part of it is unconstitutional then the market resolves to 9.

Nitpicking: I think you should explicitly state this is about the Federal Supreme Court. Some states (eg California) also have supreme courts with "justices"

Done.