the wind speed is averaged over 16 seconds and the wind gust is sampled every second. 

No the readings come over a tabletop unit. 

No not a multi channel station. However you can add up to 3 additional individual sensors for temperature, not included with the kit. 

The sensor suite does but the display is different. It is in color and bright as the whole outdoors. The Davis display is LCD. Hard to read without the light. I have owned them both . The Sainlogic is my choice as it has a beautiful display and appears as accurate as the Davis . it is also a whole lot cheaper. 

Connecting to weather underground is the first thing you need to do. Set that up first. You will see how to do this in the instructions. When you go through the set up on the WU (weather underground) you will not find this product so pick other. Continue to set it up, and make sure you SAVE or print, or write down the sign on and password because you will need it for the next step. This is the only way to get your device online.