Trump has reached out to Cruz. Unless Cruz wholeheartedly and without reservations endorses Trump when he speaks, and lets Trump know beforehand, he should be pulled from the line up.
Trump said, if theres no endorsement, then I would not invite them to speak.
As any good cowboy know, too much fence straddling could put a painful splinter into your balls.
Trump does not need a wholehearted without reservations endorsement from Cruz. After the nasty primary fight, that would come off as insincere and forced.
The theme for the night is "Make America First Again"
Trump needs Cruz to briefly acknowledge that they have differences, but Cruz will support Trump as the nominee. Then Cruz turns on a blow torch on Hillary Clinton. Few people can eviscerate Hillary and her crimes like Cruz.
I suspect, based upon the theme, that Cruz will outline how Hillary has continually broken faith with the American people and sold her and her husband's influence to foreign nations.