havent read the above, but
its pretty simple for me.
have 7? then dont do it, if you really must have it, image your machine, back up your stuff, wipe the disk, do a fresh install. reimage machine with 7 when you are pissed off.
have 8? then back up your stuff, wipe the disk, install windows 7. if you must have 10,image your machine, back up your stuff, wipe the disk, do a fresh install.
the only good thing about 10 is it slighly less shit than 8
the idea of doing an inplace upgrade is fucking stupid, it always been stupid, it always will be stupid. even if it looks like it works, it can cause problems down the line. bite the bullet, and do it properly.
ive seen the 10 upgrades do all sorts of crazy shit. remove security, remove other programs, ruin file shares and permissions, ruin network adaptors.
stay with 7 until the middle of 2020, maybe then 10 or whatever it has morphed into wont be quite as shit.