Text updates for now, videos later:
Car #2 - 1997 Peugeot 106, 60PS, TÜV 12/22, it is still at the dealership, but I am unaware of any issues. Purchased for 450 EUR (was listed for 800). 175k km or thereabouts, looks pretty clean all around. Got new brakes for TÜV and some other things I don't recall right now.
Car #3 - 1999 Opel Astra 2.0, 136PS, heated leather seats, cold AC, no TÜV, sitting on KW coilovers and has a fart can. Known issues (was checked on a lift by the dealer for TÜV reasons) include 1 broken front spring (depending on which one it is, KW sells them for 39/69 EUR) and a tie rod or something in that area. The headliner is sagging badly. Again bought for 450 EUR as is, was listed for 1000 with the things fixed and TÜV. 220-230k km, something in that neighborhood, had a timing belt job done not terribly long ago, should be fine for a while.
Car #4 - 2002 Renault Laguna Grandtour, 1.6 16V 107PS, 164k km, cold AC, trailer hitch, nothing else. TÜV 3/22, a lot of scratches and some metal blemishes, but looks tidy underneath. Exact service history unknown right now, but 1 owner car who passed away earlier this year, been mostly sitting since. Whenever something came up, it was fixed, not more, not less. Saw an oil service sticker from 3kkm and 2 years ago. Listed for 500, purchased for 400 EUR.