The required magnet coating, Mod Podge Dimensional Magic, was not available at any of the crafting Meccas around town (most notably Michaels and A.C. Moore), but I eventually stumbled upon it at a local Hyatt’s. I also purchased square magnets at Hyatt’s, then sanded the edges to make them app-worthy. In future, it may be easier to print the app icons on cardstock and then use Aleene’s paper glue as per this nifty tutorial for Pantone chip magnets.
I think they turned out quite nice-looking, though. Another victory for homemade gifts!