I hope that adaptive layers will be able to resolve at least some of your issues. It did help me a lot in the past.
I sometimes struggled a bit at reduced temps (to 245°C). While helping (lots) with overhang warping, reducing the temp also led to a worsening of a strange surface defect around 1mm mm behind the seamline on upper slopes. Hence my current attempt with coasting enabled. If all goes reasonably well, it’ll be another 2 days before I know though.
I am also going at reduced speeds (60-100mm/s outer wall, 150mm/s insides).
As for defects 1) and 3), I assume you are already considering the print order to print the outer wall first?
I have also followed advise on setting the slice gap closure in Quality → Precision to 0,001mm. While it did reduce the size of the seam, I am still getting defect 2) as well.