Thanks to the wisdom and knowledge of @tremblap and also some old posts the team made in the REAPER forum I was able to concoct a REASCRIPT script that can segment using noveltyslice inside of a reaper project. With some more effort, the other tools could be implemented.
The code can be found here > https://github.com/jamesb93/REAPER-Scripts
Installation can be a bit tricky as you have to point Reaper toward a python 3 installation, which also means you have to install Python. It would be nice to re-write the scripts in LUA or EEL perhaps, but this was more of a proof of concept than anything and I am more fluent in Python.
The script in action:
To install it, the simplest way is to download the script(s) from the link and place them somewhere you can find them again. Go to actions in Reaper (Shift + /) (or is it just ?..) to run the script once you have something selected.
To make it better I could have it iterate over all selected items, but I had really had enough of the REAPER API once I got to this point. Perhaps in future.