How do you NOT freeze?

Someone might have to confirm, but I guess in the old days, they used to apply gobs of vaseline as primative insulation.  I would not recommend starting out from the warmth.  Its best to get the crappy acclimation to the cold out of the way before the race starts as the HR will go through the roof once you get the chest, face and naughty bits in the drink.  Double up the swim caps too if you dont have ear plugs.  You should be fine cuz of the shorter distance, but cold water in the ear canal can cause some dizziness on the way out.

The big question is what is the water temp?

57 air temp is ideal for running, really. Could be a little chilly at the start of bike, and really a wetsuit isnt going to help that aspect. You'll be wet, period.

Being a sprint I would not skip a warm up in the water.

Get a decent warmup in before you start swimming (your call whether you want to swim a little, get out and wait for your wave to start, or do a jogging warmup only).  A cup of hot liquid (you could even heat gatorade and put it in a thermos) in the hour before the race can help too.  Even if you're standing on the shore in your swimsuit, keep a pair of socks on until the last minute and wear water shoes or flip-flops rather than stand barefoot on the cold sand/grass. 

Plan to dry completely in T1.  Then you can choose to dry or not when you actually get there.  If you've gotten out of the water and are shivering, a minute or two to dry off and put on a dry jersey and socks will make the ride a whole lot better.  It isn't fun blasting down the road in 52F weather when you're wet.  If you get out and you really aren't that cold, then you have the option to ride wet. 

83 degree water and 57? Sounds like a recipe for a fast race to me!