Yes but it depends on what you're playing. You should definitely be aware because the MUD deck is also real.
Probably not but if they want to I don't think Hurkyll's Recall is the answer. Something far more hateful like Kataki or Ancient Grudge is probably better.
Not really. You just need a couple pieces of incidental hate and you should be able to beat it. Add more Grips or Needles—no one needs to resort to Kataki.