Four Straight Sacrifices and a Wild Ending

Today I played a wild blitz game against a slightly higher rated opponent. In an even ending he sacrificed a piece to gain some powerful passed pawns, which led to the position below.

I had White and didn't want to passively try to block the queenside pawns. Instead, I managed to make sacrifices on four consecutive moves and still not change the evaluation of equality! What would you play for White?

The game is still even, but now Black must find a difficult defense to stay in the game. He started well, but couldn't find his way through the complications in time pressure. Best defense allows White to promote to a second queen, but Black can make a perpetual check. I did make one mistake as my clock ran down and Black could have escaped, but didn't quite find it. Finally, I was able to deliver mate with one second on my clock. 

Here's my favorite position from the time scramble. It's Black's move, but White can force mate in four.

Finally, here's the full ending, with time pressure mistakes from both sides. Black's successful defensive options are also included in the notes.