2. Repairs and preventative maintenance. We average ~4 feet of snow a year, so tie rod ends, wheel bearings, control arms, bushes, flex pipes, exhaust hangers, etc. suffer since no one really maintains a steel car properly. The reality is when even a Honda or Toyota dealer is $125/hour and a Lexus or Acura dealer is $175/hour, people don't replace $18/ea bushings -- but when things rattle or feel loose, they sell the vehicle like it's going to explode.
These aren't difficult repairs, they just require lifting the vehicle (I have a Bendpak Quick Jack) and doing it. People also don't properly clean their undercarriage, and rustproof. I do. Very easy, very inexpensive. Though when many people treat cars as disposable, it lets a lot of nice stuff come onto the market for the well-inclined.
3. Not an issue unless you're in Porsches on up with encrypted ECUs, and even then, that prevents MODIFYING them, not reading diagnostics. Regardless, this has been a problem 0 times since I've started many years ago. OBD-II is a wonderful thing, and there's no weird shenanigans coming from Honda/Toyota at all.
4. I only do paint correction, as in "level a clearcoat" to a mirror finish, and only for vehicles that merit it (let's ignore that any car sub-$150K new comes with some level of orange peel). I do not buy any vehicle that needs a respray, ever. It can be DIY'd very well, but the amount of labor is prohibitive. Not enough money made for the time spent.
5. I've an umbrella policy, mostly because I have one for my primary business, in the odd event I ever were sued. In general, vehicles are sold as-is. Zero concern here.