Lakers still planning to workout fox and meet with fultz...yet gave a promise to jackson?
Teams generally want to work out / interview as many of the top players as they can. Even players they don't expect to draft or even have a chance to draft. Danny does this every year. Danny is only allowed to talk with players during certain points in their careers when they aren't under contract and he has talked about how important it is to gather as much information on as many players as you can when you can. Similarly, on the opening night for free agency he will call a zillion free agents, even those he can't possibly sign.
I'm sure LAL is operating with a similar philosophy. Hence even if they privately gave a promise to Jackson they would be mum about that and present the image of still being undecided so that agents will send their clients in to work out. So that they can gather intel about Fox and other top picks.
Similarly, that's why Danny would be completely non-committal about his feelings about Fultz. If he came out and was all glowing and effusive with Markelle love after his workout, he'd never get anyone else in to work out. As it is, of course, Ball and Jackson have cancelled on him because their agents probably see the tea leaves clearly.