I don't know where this talk of invalidation of issued EAD's is coming from, it cannot happen. This is fear, uncertainty, and doubt at its highest.

There are precedents that courts and governments have to follow, they cannot arbitrarily and capriciously revoke privileges given by the government without proving that its ruling passes strict scrutiny, the highest level of standard of review.

What Hanen can do is to rule that the government had the authority to rescind DACA and bypass the 30 days notice and comment period required by the Administrative Procedures Act (I don't know what judicial gymnastics Hanen will perform to make this ruling).