Undocumented college affidavit for instate tuition?

Does every college in the us have a affidavit of intent for undocumented to receive instate tuition? Including the ones that prohibit undocumented from receiving instate tuition?

In-state tuition would be applicable only to state universities, not private schools.

It depends on the state as to whether there is any provision of the type you mention. If a state has such a provision, typically it is included in provisions that allow students who have graduated high school in the state with a sufficient number of years of attendance or residency in the state to claim in-state tuition (not all states have such a provision for anyone).