Calling an Audible

In my last tournament in Navalmoral, I finished with 7.0/9 and in clear 3rd place behind Fedorchuk (who beat me in a game I annotated here last I week: http://www.chess.com/article/view/building-a-fortress). I had 5.0/7 going into the last day, and it was my two wins on that final day that propelled me to 3rd place. The first of those wins was as black against the young Spanish IM, Alvar Alonso Rosell.

It was a weird game in that even though I won, I didn't really feel like I played that well. I sort of just hung around long enough for him to mess things up, and when he did, I was ready to take care of business. I did play the opening fine, which was mostly notable for the surprise I sprung on him (and myself), using a line I had never played or prepared for Black! We skipped the middlegame phase and went straight to a complex endgame, where I decided to maneuver around, thinking myself to be rather clever. Unfortunately, it then dawned on me that I was walking into trouble all over the place, and was only saved by my opponent's time trouble and his resulting oversights.

Maybe the most important lesson I took away from this game is that, even in the endgame, attacks are possible. I let my guard down thinking that the queen trade removed any danger of being checkmated, but my opponent smartly didn't make that assumption. As Stewie would say about my early endgame maneuvers, "Hoisted by my own petard!"

Question 1: What would you play for White after 17...Kb8?

Question 2: What would you play for White after 21...Ka8?

Question 3: What would you play as Black after 27.h4?

And here's the whole game in one viewer: