One
It's not scat. That's an interesting word. It means singing without words. Scat sounds like it could be words, but isn't. Elvis used scat in at least one of songs. A wob bapalop balop bam boom is close to scat. Scat uses the voice as an instrument, and not as a mode of communication.
Improvisation might be the second best answer. It seems like there are two people speaking but they are not exactly listening to one another. She's saying one thing, he another. It's really important that they get together on this, but they haven't so far. She's talking about schooling, he's talking about money.
Blues is really a musical term. I don't think what they are doing is beyond improvisation. Blues is very technically orientated. I wouldn't choose it, but if you know something about music and think that Hughes poem resembles blues, pick it by all means.
Syncopation is a possible answer. It is where and how emphasis is placed. Poetry pays a lot of attention to emphasis. There's something on U tube that has a strong Syncopated melody. Look up Sychopated clock produced in the early 1950s. It will give you the idea of what a sychopated beat would be like.
I think I'm going to change my mind and pick improvisation, but it could be sychopation if the beat is right. I have a tin ear so I'm not sure that I'm the proper guide for this answer.
Two
Swing is much later. I would use call and response. It's not quite what I would have in mind. But there are 2 people and there doesn't seem to be another answer.
Answers
Improvisation
Call and response
