The issue with standing on a principle like this is that isn't hard for a Judge to disagree with it. On NES we all focus on the exact words, the meaning of the words, and nothing more. Whereas a Judge will interpret and say for example "Well 7/20/16 was not law before, however it was notice sp the new law is good" (don't pick it apart - it's just an example of the point). There are so many ways to interpret this and at this point I think all we are doing is bench racing after having looked at it 16 ways from Sunday the only resolution is in Court.There is a problem when positions are stated as fact.
GOALs statement that the healy date in the law has no effect is just that - a position, not a determination or sound legal advice a lawyer would give to protect his client. Those who know they don't know may know more than those who do not know what they do not know.
This issue is not "did Healy have the authoritiah to issue her ban?", but "it is legal to establish a cutoff date in the past for grandfathering". The state cound have picked Arbor Day 2020 as the cutoff date and the legal question would be the same. Even a jusicial finding that Healy did not have the authority to change the law with a notice would not also establish the lack of authority for the legislature to establish a retroactive grandfathering date.
With the usual caveat of "this is my understanding, but it is only that - my understanding, not an official interpretation and got guaranteed to be correct".
On the plus side the numbers are so high it would not be realistic for a Judge to wholesale declare everything fails the test and we are all felons. This will work itself out over time and during or after such time the Federal Courts will get to rule on the constitutionality of it all.