Q: Transfer ringtones from MBP to iPhone SE

I recently upgraded from an iPhone 5C to an iPhone SE, and (in the Apple Store, with help from the staffer) initialized it via backup to MBP and restore to new phone. My custom ringtones didn't make it. I still have the m4r files on my Mac, and iTunes plays them with no problem. Although I can apparently copy them to the Tones folder by dragging them from the Finder, iTunes won't play the ones that appear to be in the Tunes folder and my iPhone doesn't find them. Three possibilities have occurred to me: (1) the SE requires a different file format (I haven't managed to find any info on that), (2) this is some dadgum new DRM maneuver on Apple's part, or (3) there's something in iTunes that I'm missing. I am inclined to suspect that the answer is behind Door Number 2. Any insights, advice, or information would be most appreciated.