Don't know enough about the Heat's thinking, but how about something like Randle for Duncan Robinson + filler/draft considerations? Both teams get rid of salaries they may not want for possibly better fits moving forward.
Heat forums seem to be almost ready to move on from pursuing Riley's mythical "whale" to just rounding out their roster with a legit PF.
Then Robinson could take something of the Fournier role for the Knicks if Fournier's moving to Utah.
Or maybe the financials override the fits on the court and neither team would benefit enough to consider this deal?