I don't think there are any black and white, yes or no, answers to the questions you pose. Here is my attempt (and just my opinion).
1. Throughout their existence: both VC and Patek have always been at the highest end of Haute Horology, with credibility that can only be established through time. It has only been since the rebirth of the mechanical watch as a luxury item in the 1980s/90s that Patek has become such a powerful Brand. In terms of quality, VC takes a back seat to nobody! But quality is not the same as market perception/value. (VC in the past has been ultra conservative and very discreet in providing information to the public - that has been both a blessing and a curse to the market. I love it from a Brand Culture point of view, but hate it when I want to learn as much as I can about the Brand's history, production, and detailed minutae)
2. There are so many within the Calavatra and Patrimony lines, it is hard to say. I would prefer a Patrimony, but that is strict personal preference - do you like blondes or brunettes, Red or White wines. One can definitely have a preference, but it doesn't mean one is better than the other.
3. Unless you are looking at the vintage or second-hand market, I don't think their are any watches in the Patrimony line that have a list price at or below US$10K. (We don't talk about grey market or discounts on THL).
4. Are you comparing the Historiques Chronograph with the Patrimony Chronograph, or with a simpler Patrimony? I am one of the few that is not too interested in chronographs, but there are other Loungers that just love them. Both the Historique's and Patrimony Chronographs are based on the same Lemania ebauche, so I would say which one appeals to your more in terms of aesthetics may be the deciding factor.
Hang around the Lounge and you will learn a lot from the passionate Vacheronistas we have here. I have learned so much from so many since I joined THL in 2007.