Yes, what you have is the proper format. The best way to submit sitemaps, of course, is to submit them via Google & Bing Webmaster Tools.

Sitemaps won't have much impact on your site unless you have a really large site, so I wouldn't focus on them too much. The best way to get content crawled & indexed by Google is good internal link structure and authoritative external links.

In the categories section in Wordpress, you can add a description for each category.  This description will then show up on each category.  This is a great way to avoid duplicate/thin content by adding a bit of unique content to each category page. Also, make sure only snippets of each post appear on the category page, rather than the full post, in order to prevent duplicate content.

I wouldn't worry too much about the extra additional links, unless you're talking about hundreds of categories. Having links to your category pages is a good thing form a site architecture standpoint.

Bounce rate is a very misleading metric. If someone visits your site, and finds exactly what they're looking for, they'll be counted as a bounce. Even some of the best sites on the web like Google & Yelp can have high bounce rates, so I wouldn't worry too much about the number, since it is unlikely to impact your search rankings.

In other words, don't make people jump through hoops just so you can reduce some percentage that doesn't really matter in Google Analytics.

One thing you can do with PDFs, though, is to have people sign up for your e-mail newsletter before they can download them. That way you can get their contact information in exchange for your content.

I think it's still a fine way of getting links, as long as you're not overdoing it.  Instead of spamming anchor text links in the footers like a lot of companies do, you could try just having a link on the homepage, or have them write a blog post about your company with an in-context link.

The page is definitely indexed by Google: https://www.google.com/search?q=site%3Ahttps%3A%2F%2Fwww.facebook.com%2FImageWorksCreative

If you just changed the URL and it used to be ranking higher, then it could be that Google is still digesting the URL change. To get the page ranking higher, make sure to link to it from all of your other web properties, such as Google+.

Also, the link to your website from your FB page is broken, you probably want to fix that!

It's fine to include tags withing an

, but including awithin an

goes against HTML conventions.

Just add the following code to the footer.php file:

YOUR_LINK_HERE

Remember that every keyword you add to your URL decreases the value of every other keyword you have in the URL. You want to include a few keywords in your URL for SEO value, but not so many that it dilutes the value of the other keywords. Also, having an overly long URL is a poor user experience.

So in this case, I would not include the word "vintage" in your URL for a 3rd time, because the SEO value is marginal and it will dilute the value of your other keywords, as well as making an already long URL even longer. And like I said, changing your URL structure will result in a loss of PageRank.

You can set up a free Google Voice number: https://www.google.com/voice

You should implement 301 redirects from your old pages to their new locations. It's sounds like you have a fairly large site, which means Google has tons of your old pages in its index that it is going to continue to crawl for some time. It's probably not going to impact you negatively, but if you want to get rid of the errors sooner I would throw in some 301s. \

With the 301s you'll also get any link value that the old pages may be getting from external links (I know you said there are none, but with 200K+ pages it's likely that at least one of the pages is being linked to from somewhere).