The Scarlet Witch made it to the chopping block rumors because reports have it that she and Vision would be in some kind of relationship in the film. However, there were also reports that implied that Vision would be leaving earth at the end of the movie, which means that the death of Scarlet Witch may have prompted Vision to leave earth for good as he finds no reason to stay.
The third Avengers superhero who also made it to the death rumors is The Falcon and that’s because he is the next-in-line to Captain America. If Captain America survives, then it could be The Falcon who will take the fall for him.
But all these are mere speculations and can only be confirmed once “Captain America: Civil War” hits cinemas in May.
It should be noted however that the Marvel Cinematic Universe is a fictional world and it is just too ironic to see superhero characters dying but Marvel did put a sample during “Avengers: Age of Ultron” shown last year when Quicksilver, the brother of Scarlet Witch, got killed by Ultron.
And besides, the trailer that was shown were the rumored deaths were based were posted unofficially on YouTube and did not come from the Marvel Studios.
However, a source privy to the movie claimed that there shall only be one actual death of a character in “Captain America: Civil War” because one hero will be critically-injured and the other one will be a misdirect.