I don’t know I’d think Trump would have the best lawyers in the world advising him here. Wasn’t there stuff published about him?
As for the accusers, if they know the accusation is false (and they are in a position to know that), then they are liable. In order for NYT to be liable, the jury has to find that NYT published with reckless disregard for the truth. In response to the Trump demand letter, NYT said that it checked the stories, therefore wasn't reckless. The women don't have that line of defense.
When there is a fact question (did he grope or not), the question goes to the jury. Evidence is presented on both sides, and the jury decides which is more believable - the standard of proof in a civil trial is "preponderance of the evidence," or "which story is more likely true." The "proved beyond a reasonable doubt" standard is for criminal trials.
Assuming Trump is telling the truth when he says the women are lying, he has a good case.
From an election strategy standpoint, nothing Trump does will take the accusations off the front page. The press has decided that decades-old allegations of Trump groping is more important than the issues. If he doesn't deny the accusation, then he is a masher, and if he does deny them, the denial becomes the news.
Totally driven by the press. The press sets its own reporting priorities.