The best thing that can happen to the Republicans is for Hillary to keep making appearances and stating her opinions!
You can't win by running against someone whose not in the race. Voter's always see this as a diversionary tactic. In 2016, Trump won by presenting himself as an alternative to Hillary because she was in race. Obama began his campaign in 2008 with attacks on Bush and it fell flat because voters had heard enough about Bush. The same is true today about Hillary.
Not really, because Hillary is an extension of the Obama administration as well as one of the spiritual leader heavy hitters of the Left. And she did garner over 60 million votes...according to some the majority of the popular vote. Therefore the Democrats will continue be stupid enough to put her in situations where she will continue to say these stupid, outlandish things and make excuses for failures of the past, in order to appeal to those same voters.
Most Americans don't see any real difference between Hillary, Obama, Pelosi, Warren, etc., they know that should Democrats win the House it will be one or another of these certified nutjobs back in power again. And then we have impeachment proceedings 24/7, even more obstruction and derailing of Trump's agenda, and we'll be seeing much more of Hillay, of course. And if republicans are lucky, Hillary will run again in 2020.