That I don't know, but the s7 author, Bill Schottstaedt (who I will ping about this) is very helpful on the email list and is deeply, deeply knowledgeable about Lisp, so you could definitely ask there!

https://ccrma-mail.stanford.edu/mailman/listinfo/cmdist

In my context, I have rigged up a REPL in Max, so I wind up using that instead. (Which is freaking awesome, because I can script all of Max from my vim buffers.)

it's trivial to implement a REPL yourself, you "just" need to poll for stdin in your main loop and pass this to S7 for evaluation. I made a demo once upon a time live coding with DearImGui: https://www.youtube.com/watch?v=MgHsl0u26MY

For the emacs side I used cmuscheme which is basically comint. Of course you don't get the same experience as in common lisp, but I found S7 to be pleasant to work with also in regards to reporting errors etc