I would not bet on any decommitment here. Mayfield knew Fleck while Fleck was at Western Michigan (Kalamazoo is roughly 50 miles south of Grand Rapids in Michigan). Mayfield may be a project at tackle as he may be 6'4" barefoot and not very long arms. Iowa wanted to see him and may have passed. Iowa may be looking for an OT commitment from guys like 6'8"Jimmy Bell Jr. (Saginaw, MI) or 6'7" Julian Pearl (Danville, IL and recent NIU commit). Iowa has flipped a number of NIU commits before so Pearl may still be in play.
I think Iowa will land Creston's Trevor Downing but he's an OG/C at Iowa and next level at 6'4".