2. I would prefer built in but usb isnt terrible
3. Color is not a big deal for me
4. 2 is enough. The iGrill 2 is going to come with 2 I believe but with ports for 4.
5. No real preference. I guess I'd lean towards waterproof.
6. I have just received my wGrill and havent been able to test it out yet. I am impressed with the quality of the build and the probes. I don't anticipate any challenge setting it up on my network. I guess my suggestion would be for a simple ios/android mobile app to monitor temps and alarm me when something gets too hot or cold.