Glad you liked it! These answers are pretty definitive, but I'd be willing to make rule-changes if something didn't feel right.
1. As it is now, it works exactly how you'd assume and wouldn't trigger. This is something I was very torn about in design, but decided to let it slide like this since there's no elegant way to add an exception. If a card like this ever became popular (in a fictional world) than people can play around the card by focusing on controlling corners. Corners are very powerful anyway, so I figure people would do that regardless of whether this card, or any similar card, exists or not.
2. Nothing.
3. The attack is ignored.
4. Nothing.
If you don't mind me asking, did you actually play the game or just glance at the cards? I won't be insulted if you didn't play it, it's a lot of work to use a print n play. If you did play it, did you use the example decks or build your own? And either way, how was your experience?
If it wasn't clear, I had a very hard time getting playtesters, and also didn't worry too much about getting playtesters since I figured few people would actually play the game. I mostly made it because I always wanted to make a card game and really liked the global-resource and win condition idea.