I ain't Tunesmith... just enjoying the thread. "Doo Wop" was an after-the-fact term dreamt up by someone to describe a particular type of vocal group. Someone must have a more concise definition but the Platters are considered "doo wop," while the Temptations are not. I don't worry much about what people mean by "Doo Wop" because all of that music was just called Rhythm and Blues. Fats Domino, Little Richard and Chuck Berry were considered rhythm and blues when they were first becoming popular.
There were groups like the Hilltoppers (who I still like a lot) who did covers of rhythm and blues groups (they covered Only You and Ko Ko Mo) whose style was less blues related, and more like barbershop.
Rhythm & Blues is like folk music... we all know what it is, even if we can't define it, and don't agree.
All these forms of music bleed into each other. Chuck Berry came out of electric blues, was considered rhythm and blues, and now is thought of as early Rock and Roll.
I'll leave definitions to someone else. I just love the music.