In the first mentioned solution after blacks 4. ... f6-e5 there is another easier solution.
5. g2-f3 e5-d4
6. f3-e4 d4xf4
7. g1-f2 f4-e3
8. f2-f3 e3xg3
5. g2-f3 e5-e4
6. f3-f4 e4xg4
... and the black piece is stuck. Any movement of pieces on fields f8 or h8, will immediately lead to promotion by the white piece at a7.
Right on both accounts. I'm glad you like analysis and I regret I don't. It's my main problem. As an inventor, I didn't need deductive thinking all that much. As a player, I forget a game after the last move and only keep certain aspects of it on the fly. Gets me all the way to mediocrity sometimes!
So I'm a poor problemist I fear.