be careful when optimizing for both, you might end up in a situation where it will look like keyword spamming. I personally wouldn't optimize for both in the page title, just the primary. And then optimize for the secondary and the primary one in the H1,H2 to Hwhatever..

You don't want to look like a spammer.

Google / Bing will understand that your plural keyword is probably the same. But it will rank you better if you optimize for the exact match key-phrase. So my advise would be to keep focus on the one with the most searches and mention the other a few times. That way you get both, but make sure that the language is something that makes sense and reads well.

Google does not support html sitemaps and will only crawl them as any other webpage. But you can submit more xml sitemaps both in bing and google. I personally use a program called sitemap generator.

Hi there

Actualy your website host should be abel to handle this for you, if not you have a seriusly shitty surplier

What you need to have them set up is more commonly known as a "domain alias" so you set up the webhotel with the primary domain and then have them set the other domains up to be aliases to that domain.

Or you could use the geeky way out. Set up all the domains to point to the server on where your site is hosted. Have your host setup your server to accept the in coming domains. and then setup the .htaccess (on appache platform) to 301 all other (including subdomains www) to the primary domain.

But the easier way out is clearly to have your hosting company set it up for you.