They will def. kill Hawkeye he's the one with the established family and kids so once done right the impact of his death would satisfy the most rapid fans finally calling for someone to bite the bullet in the MCU movies.
If anyone is going to die I believe it will end up being Hawkeye, they won't kill off any of the other Avengers and if they do it'll just be temporary.
If a shitfest like SS and BvS with a RT score of 27% could make 700 / 850M WW then Doc Strange being backed by the Marvel brand of critically well received movies could easily sail past 1B WW.