How to Add a Post Category Page with Conditions

[Ozias]

Warning! I am learning!

I came across instructions on "How to Add a Post Category Page" - http://dev.studiopress.com/add-post-category-page.htm.

This is excellent but I would like to go one or two steps further. In addition to creating a post category page, I would also like to be able to:

(1) Create a post category page which only shows posts within a certain category AND within a certain taxonomy or multiple taxonomies.

The second part of my question may be more difficult. I would like to add an expiry date to my posts with the idea being that once the date has passed, the post would no longer show on my Post Category Pages. One idea I have is to create a custom meta box with the date field allowing me to add a date in the future to my posts. If I go this route I have a question:

(1) How do I create a post category page which only shows posts within a certain category AND excludes posts which have a date older than todays date in the custom meta box date field?

Last but not least:
(1) Is there an easy way to add the fields in a custom meta box to a post? Using the meta box with the date field as an example, how would I display the date field in a post, but not all posts, just certain ones based on various criteria? Is there an easy way or some short code which will allow me to add the fields from a meta box to a post without having to change templates and such?

I am very appreciative of any responses. Thank you and have a great day!