Yeah, I saw those pictures but there isn't much detail in them but your description is probably enough to make a quick judgement. Since you're not intimidated by doing the wrenching, the cost may be an issue you want to explore. Given that you want a Europa at a level higher than the $12,500 car, I think it would be less expensive to get there starting with that car than the basket case. There are a lot of variables, of course - the relative condition of the frames, motors, and trannies are the biggest.
I just saw 4129R's post which reminds me that the history of the $12.5K car matters because if it's been sitting (especially outdoors) extended periods of time, not only the rubber but likely all brakes will have to be gone through and replacing a lot of that will add a lot of piece of mind.