I found the help files - I see Weather Underground. I assume then if I publish to WU then I can use my data but could I kinda like my data staying here as a matter of principal (not really bent of weather data though) but could I use the Tools to connect to the Weather Underground feed from the station and provide it to the BI Tools Overlay and possible inject other sensor data as well?
Yes, if you have your own PWS and it's uploading data to WU, you can pull that weather data through BIT and use it as overlays. You can also inject almost any other data into an overlay as long as that data is stored in a local text file that BIT/BI can access.
If you can put all of the data on the display BI can do a screen capture as a camera.
You just have to add a camera, other, then select screen capture. It's won't be an overlay,
but will at least get the data saved along with your other video.
You could probably use one frame a minute or less rate.
I used it to record a web site with several cameras, worked well to get the over view.