Nicely summarised, Mike
It's worth noting that provided you're going to put the stars back in a narrowband image after processing the colour there's no need to do a perfect job of star removal. I've got some excellent results from just doing a big star reduction on the Oiii and Sii masters before combining them with Ha.
If I had the time I'd have a go at writing a PixInsight process to do star removal. Unfortunately, I don't think it is something that would be amenable to scripting and my C++ is a bit rusty.
Cheers,
Rick.