It looks like ChatGPT was hallucinating a little bit when it answered your second question. Yes, the trial-level judge who originally dismissed the case against Hikma can dismiss the lawsuit again, but only after both sides have the chance to gather and exchange evidence, including emails and correspondence that Amarin will hope contains a smoking gun or two that will further illustrate Hikma's bad intentions. At a later point prior to trial, Hikma will again move for dismissal of the lawsuit on the grounds that the judge can find as a matter of law that Amarin cannot satisfy the legal points necessary to take the case to a jury. And, at that stage, the rules of the game will not be as favorable to Amarin as they were at the current stage, when the trial judge was supposed to accept that everything in the lawsuit was true.
ChatGPT makes it sound like the judge can respond to the appeals reversal of his dismissal by merely writing the equivalent of a legal essay back to the appeals court to better explain why he threw out the case in a way that he thinks the appeals judges might accept.
With a reversal, three judges on the Federal Circuit (assuming its a unanimous ruling, which it certainly seemed it will be based on the tone of the arguments) will be telling the trial judge that he was wrong. The judge cannot then merely "choose to reaffirm its dismissal of the case" if he "believes that its original decision was correct." That's where ChatGPT was hallucinating.
Judges don't argue with each other that way. It's very much like the military. The lower court judge will be told politely by a superior (the Federal Circuit) that he is wrong. If he tried to protest and insist he was right, the higher court would take the gloves off and scold him like a small child. And he'd lose the respect of his fellow judges. I've been watching courts closely for nearly 50 years. This would never happen!