WordPress custom post type advise

I personally would do a custom post type for photographs, and custom taxonomies for venues and seasons (or probably a hierarchical taxonomy that used venue and season in one).

As for archives – archives.php (or archive-custompost.php) (or taxonomy-custom.php) are simply templates. You can add whatever you want to it. As for saving “page” data, you currently don’t have the best options. There are several ways of doing it – and there are Taxonomy metadata plugins – but true Taxonomy metadata probably won’t be around until WP 4.4 at earliest ( https://core.trac.wordpress.org/ticket/10142 )

You could also make a shortcode to pull all the content for the archives, and put that shortcode in the “Pages” that you make manually. As actual pages.