There is no way for me to say, with any degree of certainty, that you are guaranteed to be AFB ridden. EFB is non-spore forming, so your rehabbing should take care of EFB concerns. AFB spores can embed in cracks and crevices and get buried under propolis and wood glue. If I KNEW that a box previously had an AFB infestation, I would never try to rehabilitate the equipment for future use. If I knew the former beekeeper and trusted him/her, spoke with them about any issues they might have had and got reasonable assurances that the boxes were clean, I would feel reasonably good after taking the measure you state above.
If I am buying off Craig's list, it would have to be one hell of a deal to make me take that chance. If I did it, I would isolate all of the equipment in an outyard and keep a hive tool in that yard for just those boxes. May not be possible for you.