All good advice. No difference between pages and posts. It's all about how they're linked to.
For #1, if your pages are linked to in the nav bar, from every page on your site, that would explain them ranking higher than posts that aren't as well linked-to.
If you're relying on category links, your posts will be 3 levels down, at http://yoursite/category/yourcategory/yourpost. You can improve this with a plugin or some code to strip out the /category base, to get http://yoursite/yourcategory/yourpost -- but that's still 2 levels down. Best to link directly to important posts -- from the home page, or a well-targeted page, as in #2.
Thesis has a sidebar widget to show the latest posts from a category. These are direct links. If the widget doesn't fit your design, you can do it with a line or two of PHP.
If you want to link from a targeted page, as in #2, Thesis has a field to add text/html to a category page, turning it into a regular page with a list of posts. But you'll still have that pesky /category base, unless you strip it out with a plugin or some code.
You can also add posts or a category page directly to the Thesis nav bar, which lets you link to whatever you want.
Unless there's a compelling reason not to, always set your Wordpress permalink structure to just %postname%
