#2 - Hulk Hogan
Back in January, Hulk Hogan made his first Raw appearance since being fired by the company back in 2015, but the company did bring him back several months beforehand at the Crown Jewel show in Saudi Arabia.
Since he's officially back in the company, one would expect to see the legendary "Hulkster" make an appearance at WWE's biggest show of the year. If he does appear, it'll obviously be in a non-wrestling role, and it's unlikely that WWE would be okay with the 65-year-old Hogan doing anything physical.
As for a potential role for Hogan, well, he could do something with John Cena either backstage or in the ring, and by in the ring, I certainly don't mean a match. However, he could be in Cena's corner for the former 16-time WWE World Heavyweight Champion's match, which will be, as of this writing, against a mystery opponent.