DS18B20 Issues - all I get is 'null'

I don't think bluetooth or CC3000 would cause you any problems... I've done some CC3000 + DS18B20 temperature sensors so I know that they both work together... Just in case it might be worth unplugging it (at least from VCC) though?

You mentioned at first that you bought 5 sensors... Have you tried any others? It could be that this particular one is dead...

Just to be sure, you can also totally skip using the DS18B20 module, and can see if any OneWire devices can be found on the pin:

var ow = new OneWire(A0);
ow.search(); // should return an array of devices