Thanks for your post,
The page you are referring to displays portfolio options found on the portfolio item New/Edit page, If you click on portfolio >> Add New you would find layout and gallery settings.
You can find all related portfolio settings on the portfolio item New/Edit page itself which will allow editing the portfolio item alone.
For more settings on displaying the portfolio listing page, you could use the portfolio page template and you’ll find layout settings on the page Edit.
I’ll get back to you on the page title “portfolio” we’ll try making the page title display the portfolio item’s title instead.