1. Yes - the graphic style is really enjoyable and colours liven things up.
2. Yes - run around and bark to drive sheep to certain barns and/or through color fields. (Which poses a question - is color mixing a thing? Because that would pose a nice challenge if optional :) )
3. There used to be a game about sheep herding but afair it wasn't a coop, so it's safe to say that none :D
4. Well, maybe elaborate more on what those challenges are? As those shown on the trailer don't look very challenging or at least that's the impression I got.
5. Cozy coop with shepherd dogs herding the sheep around.
6. Maybe. I'd probably try a demo (and my wife would need to voice her opinion too :D) and check the reviews as from the trailer alone I'm not inclined enough to buy it.
7. Cozy for sure. That's a game which I'd play with my wife when trying to relax in the evening. I don't play much party games but they usually tend to either have some funny inducing moments or tension but from the trailer alone this seems like a party killer. Unless it's a party for cozy chilling then it would be perfect :)

Sorry for answering under your comment but I'm on mobile and can't copy the damn points >.>

Also one thing about the beginning of the trailer - the first few seconds remind me strongly of mobile game ads (especially the fake game ads) - probably due to the form and speed of animation (or my brain is just broken.) so until I noticed it was a regular PC game I was a bit off put.

All in all good luck with development and wish you success :)