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If content is the same through all of these versions, then I assume it would be good to have http://www." in all of the versions. Of course if redirect is an option, then that would be better.

1. Domains

If the page content is identical, then yes, you will probably face duplicated content issues.
You could use rel="canonical" tag to inform Google which version of the page is original. As you probably know rel="canonical" is not bullet proof, it's more like a recommendation for G.

BTW. On Google Webmaster tools you can specify which country you are targeting, although this will not erase the duplicated content issues, it might be worth to use.

2. Adwords

It's a bit unclear for me what you meant with redirecting AdWords traffic.
I would do different campaigns for different domains. If the domain changes, just update the URL's to your AdWords campaign.

Deleting the duplicate posts works. If the post has to be kept in two places you could use rel="canonical" tag to let Google know which is the original version.

Directory submissions are not very useful. Bad directories can even be harmful (Note. confirm form someone who has made research about directories). You also need to focus on your linking profile. Linking profile should be natural. If there is large peaks on the amount of links, it might be alarming in the "eyes" of search engines.

In some business fields highly specified product directories have still big role in generating traffic and leads, but that's another story.

If you find respectful and relevant listings, then go ahead and submit. If the only reason to submit links to directories is to get better rankings, then - in most cases - it might be a waste of time.

One word: Natural! Create good content and try to get natural links to your site. Of course you can contact people and notify about your great content. They might like it and link to it. Don't just send linking requests though.
I wouldn't take part to shady link building schemes, blog spam linking, spam blog linking, link swap (if not natural) etc. Of course there are people who can provide you thousands of links fast, but in long term it probably turns against your site.

Hello Eblan!

You probably have also tried to get links from these non-profit organizations with whom they are working with?
You didn't mention social media at all. It's probably lively in Mexico? You could try to create campaigns using different social media platforms around the free giveaways to get some social mentions.

Deleting the duplicate posts works. If the post has to be kept in two places you could use rel="canonical" tag to let Google know which is the original version.

Hello Eblan!

You probably have also tried to get links from these non-profit organizations with whom they are working with?
You didn't mention social media at all. It's probably lively in Mexico? You could try to create campaigns using different social media platforms around the free giveaways to get some social mentions.