Alright! Progress.
While I was on the bus, @unlambda looked it up and pforth *has* a symbol-by-symbol trace (it's called… TRACE). Unlike most things in pforth, *this* feature is well documented. Now it also requires me to use INCLUDE, which *isn't* documented, and which I couldn't get to work, but n/m, I just pasted the whole program into the terminal each time.
What I found: Remember me not getting `CHAR A` to work, and experimentally finding `CHAR 'A'` as substitute?
…It's not a substitute.