WordPress for Content Management?

I believe the only way to do that is to use the same site template, just do not add the wordpress code.
Maybe someone elce can comment, cuz im not 100% sure.

You can do that by attaching a .CSS to the other pages you want to create. That’s the only way I see of doing it. I have skins or themes on my blog and I finally decided on one .CSS for the portal page, not skins.
Is that what you meant?
??

I have used WP for a news-oriented website (still in the works):
https://chechnyapeaceaction.org
The Link manager and its associated tags are very powerful.

Or you can do some tricks using php code (in particular the ‘if’ condition and the ‘isset’ function). In this case you’re don’t need to create new pages, you just use the index.php page.
That’s what I did on my website https://sieste.defloy.com/ (still in dev version)
The content of the homepage (aka “projet”) and the “conditions” page is made of blog entries but not displayed as blog entry, it is displayed as single article without the title and other article’s informations. The blog is displayed on the “nouvelles” page.

If you use the solution of creating other html or php pages, in order to edit them online you just need to add the folloing entry in the b2menutop.txt file to get the edit option in your admin menu:
6 b2template.php?file=yourpage.php Edit my page
(yourpage.php = the name of the page you want to be editable)