Stu Feldman developed make(1) and touch(1), which were tools that came with it.   This work was initiated on Research Sixth Edition, which was evolving into something that, as a kernel, was sometimes referred to as UNIX/TS.  As to when Stu started using the TS kernel over the early V6 kernel, that has been lost to time. The same applies to the compiler.  He might have started using an earlier C compiler that linked with libS.a before stdio was fully integrated into libc.a as it would later be.  But I'm sure it was by the time his work was complete.

Remember, there were no formal names.  As the Research team and the Summit (USG) teams worked together and shared changes, differences were identified, such as in the kernels and specific tools.  The release vehicle for the final kernel from Ken and the tools to folks outside of the labs was what we call the, which generally predate PWB 2.0 by a small amount.  Remember rleeease internally were tad more fluid (like git clone but without a release guid).   Also the tools like make/touch were also included in the PWB via the Summit releases. Stu's paper is included in the Seventh edition documentation, although it came from Research not Summit.