OPer here. I had no idea that the situation would develop in this manner when I first posted.
What is really surprising to me is the move from ok with a solo / self-reliant cert to no solo diving at all with some of the operators like Buddy Dive.
I am wondering if Buddy Dive's change in this specific policy is the result of Fiona Sharps' death some time after the original post. On a trip prior to her death, I had a conversation with a random diver on the subject of solo diving on the Buddy Dive dock. At the time, they had no problem with solo diving at all.
Dive Friends, (who I did not identify in the original post, to the irritation of some) used to not have a problem with solo diving even without a certification until one of their instructors died from lionfishing by himself. It appeared that their change in policy started some time after that happened.