I would like to chime in on the hotel options:

1. Best option would be to use Starpoints. SPG rocks in situation like this.

2. Stay outside of Venice to save a few bucks. You can do a search for hotels in Mestre, which is about a few minutes train ride away from Venice. It's like a commuter rail that runs every 20 min or so. Hotels in Mestre can be had for about $150 or lower. Look for those that are near the train station for convenience.

3. Near VCE airport, Antony Hotel is close to the airport. It is about 10 min to the train station.

Enjoy Venice!