The "not part of the camera roll" was an important distinction. That makes more sense. I've not ever put images back onto the iPhone except in one case where I needed to take 2 or 3 images of my daughter to show a friend. I did find it a total PITA to accomplish this for 3 images. It would have been nice to simply drag the images into iTunes like with music or video and just have it copied to the phone.

Unfortunately there's no way to have Lightroom delete images from the original device during or after importing. And if the imported images are being merged into a large collection including images shot with other cameras, there's no practical way to get images back onto the iPhone (outside the roll) automatically either. The best alternative I can find is to make a duplicate of iPhone imports to an alternate folder. That would need to be saved as a preset and then that preset carefully applied (manually) only to iPhone imports so it doesn't duplicate images form other sources. Then that location would need to be set up in iTunes as an import folder.

Unfortunately this won't allow any image operations. To do that one would have to follow the other export/publish tip and instead handle it all in a more manual fashion. Do the import manually, then use Image Capture to delete all the images from the iPhone and then back in Lightroom perform the publish of your last imported photos. Then back in iTunes, Sync, including Photos.

Seems like a huge PITA. But then Adobe isn't exactly known for smooth workflows. Everything they create is a giant bag of hurt. In this case I'll lay some of the blame on Apple for not making it easier/more straight forward for other apps to integrate with iTunes as well. Unless of course the current mechanisms are able to be used and simply aren't being so.