They didn't show up greyed out but didn't show up at all- even when show all photos was selected and Don't import suspected duplicates was deselected.
Where are they not showing up? Exactly where in LR or where in your operating system are you not seeing them and you think you should see them. Be very specific. Show us a screen capture.
They don't show up when I try to import them. Other photos are there, but not all of them.
So you are importing photos, and some of the photos on the iPhone show up and are imported and others are not?
The first thing that comes to mind is that the ones that don't show up are the JPGs and the ones that do show up are the associated RAW images. Could that be what you are seeing?
right, some show up others aren't.
All are JPG files. Google photos backed all of them up.