If you are not gonna' be doing a lot of gun hunts......I would go with the Z1U. It is much better than the V1U in low light. Add a wide angle lens and it is even better.
I have pro's and con's on each camera and prefer the Z1U only because I have the most experience with it. Give me some more time with the V1U and I might prefer it.
I don't know anything about the Z7U.
Why shoot on the last day what you wouldn't shoot on the first?