Update:

My agent just called me to give me an update on all three houses that I gave offers to:

1) the first house: entered escrow already, so there's very slight chance they will come back to us;
2) the second house: my offer is too low, but because we are serious buyer (with high loan approval amount), we might still get a counter offer back. According to the selling agent, the house has been in and out of escrow twice -- both due to loan problems. So we might still have a chance to get it if we increase our offer;
3) the third house: my offer is 3% below the asking price, but the selling agent has three offers in hand already (after 1st day showing), and one of them is over-bidding.