I agree as well that notes an octave apart aren't harmony. But street legal. If you have five people singing, you have to cheat somewhere. In both doo wop and black gospel groups, someone singing an octave above someone else's note in falsetto is one option. If there are enough harmony lines to fill in the spaces, that sounds great... a nice balance to a walking bass line.

A year or so ago, I invited someone who'd sung with three or four classic doo wop groups: the best known being the Flamingos (I only have Eyes For You.) He introduced me to the concept of "push harmony." I'd never heard of it before (or since, for that matter.)
Someone who is singing push harmony sings a simplified melody line, "pushing" the lead singer and strengthening his lead. That makes a certain amount of sense as in a five man group with all the harmonies wailing out, the person singing push harmony can help the lead singer stand out above the background. Unfortunately, our attempt to integrate the person into our group didn't work out, so I didn't get a lot of working experience singing push harmony. But, it's something we'll be talking about with the bass singer from the doo wop group who is joining us. He's sick this week and won't be able to make practice tomorrow night, but he does all of the arranging for the doo wop group, and between the two of us it should exciting, working out the harmonies together in a way that respects both styles of singing.

This year, if we do the Church And Street Corner Harmony workshop at NOMAD, we'll have a lot to share from these next few months of working together.

I really appreciate all in the input to this thread. It's part of the growing process.

Jerry