I can get 5 of them onto the phone, but not all of them. I have 9 custom ringtones I generated myself. If I choose only 5 of the 9, I only get one or two on the phone.
I wound up doing some searching, and from a post on a Verizon Community forum, I got the answer that worked for me. First, I unchecked "Sync Ringtones" and ran a sync. then I re-checked that same box and ran another sync, and voila! All of my ringtones are now on my phone, and I can now assign them to the people I used them with before.