Pages are found by the search engines, just not as quickly as posts because the search engines are automatically pinged when a post is published. Pages end up waiting for scheduled crawls by the search engines. My suggestion is to keep pages for content that seldom changes (about, etc.) and then use categories to group posts by subject. This is particularly true if you are going to be adding content regularly.
Static front pages do decrease ranking, but if it makes sense for your content I would go ahead.
I'm not sure on the front page as a post thing. I've never seen an entry in my stats for the front page.
If you use a static front page, I would not allow comments there, but it certainly would not hurt anything as far as ranking and such.
http://nina80.wordpress.com/ is still showing that it is not indexed by Google according to http://ismyblogworking.com/nina80.wordpress.com . I think the reason for that is that you have not published any posts so wordpress has not pinged the search engines.
My suggestion would be to actually force the issue with Google by doing a verification using Google WebMaster Tools as outlined in this support document: http://support.wordpress.com/verifying-with-google-webmaster-tools/ . Instead of making a page for the google verification, you can make it a post and then after google verifies your blog, edit the post and set the date to a point before you created the blog so it is out of the way and doesn't show up in your pages list. This support document explains how to change the date on a post: http://support.wordpress.com/posts/schedule-a-post/ .
Also, just to make sure, go to settings > privacy and make sure that the top selection is set (to allow normal visitors and be visible to search engines).