Both SPWG and the already proposed Swift Tooling Workgroup will be dedicated to improving user experience of Swift on supported platforms. While the areas may unavoidably overlap, I see SPWG more of handling platform-related features and bugs, and STWG focusing on general usability improvements. It seems your requests are mostly related to the tooling side.
I would like to see these two new workgroups come into reality and work together. For user feedback, we may introduce a single Slack workspace for the two workgroups, since the two need cooperation frequently by themselves. There could be platform- or tool-specific as well as general channels for user feedback, and so both workgroups can be involved. WDYT? @0xTim