Passing and retrieving query vars in wordpress

I have two authors pages, one displays about 5 posts. Then I’m trying to setup another page that will be all of their posts. I have created a template called moreauthorposts.php and I’m trying to pass the author variable to this page. Problem is if i pass domain.com/more-author-posts?author=johndoe it gets stripped out. How can I retrieve this value? Is this even possible in wordpress? I know WP Rewrite is jacking my URL structure somehow I’m just not sure.

Get the current page URL (including pagination)

Is there a WP function to automatically get the correct URL of the current page?
Meaning if I just opened a single post, the function returns the same as get_permalink(), but if I’m on a paginated instance of a page (when paginating through the comments), the function returns the same as get_pagenum_link(get_query_var('paged')) would do.