Who Will Win? Braun Strowman
He has to doesn't he? From a purely logical standpoint, it appears to be the only booking choice unless WWE decide to go the Double Disqualification route or another method that the two combatants could draw if WWE does not want either of them to win the bout.
However, if WWE really did want to put the Universal Championship on anybody else, then surely they would have booked a substitute when the reigning Champion, Roman Reigns was forced to withdraw from the match and vacate the title.
A win over the dominant Lesnar character will enhance Strowman greatly and erase memories of his chastening defeat to the "Beast" at No Mercy last October, wherein Lesnar beat him in a paltry nine minutes.
Strowman has to defeat Lesnar to win the vacant Universal Championship and he will.