This is all sorts of wrong, you need to first decide if you want to use posts, pages or custom post types.
You alluded at the end that you wanted a new tab like you have seen in some themes, this would be the right way to do it using Custom Post Types.
You can learn how to create them here,
http://codex.wordpress.org/Post_Types#Custom_Types
http://codex.wordpress.org/Function_Reference/register_post_type
After that you can create a template file for your post type that is specific to how you want it to look. For instance say you created a CPT called “Gallery”, your theme file can be single-gallery.php. There you can use the loop anyway you want to display and style your photos, and every post made in this post type (Gallery) will use that theme file.
To answer your second question, when you register a new custom post type there are parameters, one of them can enable or disable the editor. The one your looking for is supports --> 'editor'
By default to manage the post’s photos you click on Add Photo—>Gallery–> there you find the management options. If you want to customize a new photo management “console” you will have to make another question as it would be to complicated to go into details here, I have seen them but I’m not entirely sure what the best method is to accomplish this.