There is the concept of "ex post facto law" which should prevent the legislature from now enacting a law to make illegal conduct or status which was legal when it was taken.
The legislature moved in haste when enacting the 2 university requirement as it did not at that time provide for the consequences of one latter deciding to go back to its original name or another name which would result in there being less than two University of Louisiana schools or provide in the law that once a university joins with another to have the "University of Louisiana" name, it legally can't go back to another name without permission from the legislature. Hard facts make bad law. Too bad for them. Under the concept of "ex post facto laws" the legislature would not now be able to remedy the actions (enactment of a bad law by them) taken in haste.
Furthermore, I am not sure how the legislature would have even come up with a law that would reasonably address what happens when one changes it mind. That would create a situation were the tail would always be in a position to wag the dog.