In the comment section on Kathryn's Report are a few hints regarding the pilot and his past activities
http://www.kathrynsreport.com/2021/01/c ... ident.html

With all due respect - 20k for an upgrade to a highly sophisticated state of the art avionic package is not a realistic figure in the certified world. Just for the sake of argument: a single Avidyne IFD 550 is north of this figure. Even so the Dynon HDX AML does not include any Diamond airframe (nor...

There has been obviously way more damage over the years than just that light wingtip scratch you metioned.
Instructions for painting see AMM 51-20-00. Some special materials are required, like anti-static filler and specific paint (AMM 51-30-00)

There is no "legal requirement" for a stall horn. That little reed broke in my stall horn - stall horn was non-mission capable until the replacement came in. Was only one or two flights before my replacement reed was delivered - but POH did not specifically state the aircraft was not airw...

in general: yes. Only a few caveats. A lot of good information https://www.youtube.com/watch?v=V_MCnhsZf6E