I would add that there's is no text on any of those three pages - any "text" one would see there is actually just embedded in an image - which is a huge issue for a number of reasons:

1. Search engines see that there's no text - a big no-no.
2. You're getting practically no SEO value from the content that would be there, even if there isn't much.
3. It's heavier this way - which makes load times slower.

I want to clarify that there are many, bigger issues with these pages - but as your question concerns only duplicate content, I'll leave all of that out for the time being. To summarize, Google, Yahoo, and Bing are just seeing some duplicate banners, sidebars, etc. and then some images in the body of your pages. Hence, duplicate content.

Yes, but I'd also make sure to do it in small bits at a time. Meaning, don't change everything at once. Make a small change, wait a bit to see the results, and if they're good, then make another small change. If the results of the first change aren't what you want, then rethink your keyword strategy and try something a little different!

Good luck! Give an update in a while if you can. I'd be interested to hear what happens.

Descriptions don't really count when it comes to unifying your brand across different platforms/sites in the sense about which you're asking, but I would still try to keep your descriptions similar. If nothing else, it clarifies to users that your page on abc.com is the same business/etc as your page on xyz.com.

Use Google Tag Manager: http://www.google.com/tagmanager/

Google Tag Manager allows you to set different "goals", "events", and other criteria. It also links directly to GA, showing the data from GTM as you set it. For example, on one of my client's sites, we use GTM to see how many people use a special offer we have set up, as well as how many conversions are made directly from the homepage, and how many visitors view but don't purchase anything from the small delivery pages we made.

Any amalgamation of pages, processes, triggers, goals, etc. can be made into a specific, tracked item with pertinent information. I also suggest taking time to acquaint yourself with the FAQs for GTM, as it can get as complicated as you desire.

If your client is adamantly opposed to having the better of the two consume the other business, then yes - the only other viable option I'd see would be to treat them as completely separate businesses that are only related by owner. Name, address(es), phone number(s), email(s), etc. should all be changed if that's the case. For all intents and purposes, they would have to be treated as two unrelated businesses.

I hope your client will chose the prior solution rather than this, but I imagine either would be better than continuing in their current state. Good luck to you.