To my understanding, Trump has stepped away from his businesses to run for President. If he then bills all his campaign time to the businesses he stepped away from, I believe that would be considered fraud.
Trump appears to have put all of his businesses into some form of “blind trust” situation where his family and business associates run the businesses while he runs for President. Because he is not involved in the day-to-day operations of non-campaign business, drawing reimbursement and/or salary from the campaign is the legal and ethical thing to do.
Finally, if campaign expenses are redirected to businesses, that would appear to be a violation of campaign finance laws - undocumented and illegal contributions from said businesses.
He hasn’t done so yet. I heard the interview. He will do so when he assumes the presidency.
You are incorrect. He has not stepped away from his business interest nor is he required to at this point. If he is elected President then he is required to step away.