Not a lawyer. From past start-up legal experience... it depends on the state. In some/many states, an employer unilaterally changing compensation for a portion

Not a lawyer. From past start-up legal experience... it depends on the state. In some/many states, an employer unilaterally changing compensation for a portion of an employment agreement, without asking employees to resign an updated contract, would render those portions of the agreement null and void. Some states have employment laws against certain non-compete and [iirc] blanket IP assignment clauses. In those states, even if employees sign to those clauses, they are still void according to state law.