Wow really nice stack, did the star flares come in camera or are they a post effect? How do you remove noise from hot sensor, dark frame sub?
when u got conected Telescope like thes guy got u can shot in low iso so lower noize..
the colour what u see on photo its gas what is invisible for human eye in this form..
only long exposure and show u this what can see..
noize is eazy to remove with extra software like Photoshop or Lightroom..
in Photoshop whenu editing TIF u can click Adjustments TAb and u got there all setings u need

.. for kill noize ect etc..
Edit :
Stars are real...
and maybe this sounds weird but i got less hot pixels with higher ISO...