Nope.
Nope
Install msfs on separate drive is good idea.
Depends on addon size.
Important is that MSFS 2020 Premium Deluxe with WU1,2,3,4 all liveries, aicrafts, airports (without freeware EDLP) install size 128GB.
Freeware EDLP download size 13GB // install size 3.8GB
My all addons size - 171GB