Are the different views going to be substantially different pages or a reordering of products seen throughout each view?  If the latter is the case I wouldn't use rel="canonical" for each view.  If the pages are substantially different, like one is just displaying widgets, while the other is displaying widget maintenance tools, the having each of those pages as categorical sections to your store is worth it and worth being in the sitemap.

Hi Alec. I'd use the Link Intersect tab on the Link Opportunities tool in Open Site Explorer: https://moz.com/researchtools/ose/opportunities/link-intersect?site=yoursitehere.com, to compare your site with some of your competitors. In this way you'll find sites that are more like niche hubs for your topic and get an insight into how and why sites in your field are gaining links. These types of sites (or just pages within a site) make up more links than the classic directories like DMOZ or Yahoo.  Cheers!

Google's guideline is here: https://support.google.com/business/answer/3038177 with the most applicable portion  being in the address section:

• Make sure that your page is created at your actual, real-world location.

• Use the precise address for the business rather than broad city names or cross-streets. P.O. Boxes are not considered accurate physical locations.

• If you need to specify a mailbox or suite number within your physical location, please list your physical address in Address Line 1, and put your mailbox or suite number in Address Line 2.

• If your business rents a temporary, "virtual" office at a different address from your primary business, do not create a page for that location unless it is staffed during your normal business hours.

So his locations need to be staffed, open to the public, office based locations. If he's serving clients in 4 different cities, but only has one office in one city it's not the same thing as the requirements above. That would be, "Service-area businesses--business that serve customers at their locations--should have one page for the central office or location and designate a service area from that point. If you wish to display your complete business address while setting your service area(s), your business location should be staffed and able to receive customers during its stated hours. Google will determine how best to display your business address based on your business information as well as information from other sources. Learn more about service-area businesses."

The document as a whole is worth the read. Cheers!

Doubtful. Several sites mentioned on their clients page are showing numbers in OSE.  Try out a few from: https://sucuri.net/clients/.  Chances are you have a robots.txt issue blocking OSE, the site is brand new, or it's on a tld domain that is currently not compatible with OSE, such as http://example.website  If you list your site here more details could be provided. Cheers!

Getting precise numbers on such a broad topic will likely be a bridge too far, plus they start to move and oscillate into the future so some projection factor is going to have to be used for any sort of planning as you make them. For example, look at Google Trends analysis of the topic LEGO: http://www.google.com/trends/explore#q=LEGO&cmpt=q.  And look at some of the ways it begins to get messy: Is it just the industry of toys? What about the movies LEGO is now producing?  Or are Legoland searches at the core of it?

The broader net you cast the more odd intersections you're going to come across...

It sounds like you're trying to use these numbers not as an industry report but for actionable budgeting and tactical planning for the nationwide business. Or maybe I'm mis-reading your question. The point being, your existing business should have some reliable numbers on current conversion rates and traffic that are much more applicable to scale into other locations. Why not use those and first apply some level of market penetration based on demographics and populations?

TL;DR: I'd project some simple trends for the industry, but then be tactical on the small scale. Work where you can move the needle most.  Cheers!