Thanks for holding this, but please carry on now, I've not a clue.
As I believe this is unlocked I will answer:
- When was this car built: 1963/64
- Where did the headlamps come from: Fiat 1500
- Which car did the rear styling resemble: Borgward P100
- Which car did Walter Schätzle build later on: AWS Shopper 250, Goggomobile based. He also assembled around 140 Borgwards with leftover parts between 1963 and 1967.