Maybe a good wakeup call for Delta to collaborate more with their regional partners when it comes to things like this. Compass uses iPad's and has wifi. It's hard to think of a reason why they shouldn't have access to the FWV. They are flying the same Delta passengers.
With the weather in the area it doesn't seem like there would be a smooth ride over the Sierra's, but it's also hard to know what type of information they were given by dispatch and ATC. The Compass crews are professionals, and I highly doubt the FA's would have been out of their seats if the crew had any idea the ride was going to get bad.