Hey there, welcome to the community! Sounds like you've gotten the ball rolling with web development already.
I find OOP to be very beneficial once you understand it at length. MVC can be a great way of conducting OOP. If you like learning for videos you should check out this: http://www.killerphp.com/tutorials/object-oriented-php/
Following this following tutorial would also be rather beneficial:
http://anantgarg.com/2009/03/13/write-your-own-php-mvc-framework-part-1/
I believe some of the more obscure engines on this board have used a number of the techniques you've listed. McCodes and NWE are procedural, but NWE was written by a somewhat genius so could be good to check over the source code anyway.
I think EzRPG was OO, but I'm not sure. Seems to of gone very cold! http://makewebgames.io/forumdisplay.php/328-ezRPG
If you wanted to go for something which isn't strictly a game engine/framework there are loads of great recent releases, check some of these out:
http://laravel.com
http://www.slimframework.com
http://symfony.com
CodeIgniter can be good for learning as I quite like the documentation but I'm not sold on it's structure, I found it "messy" to work with:
http://ellislab.com/codeigniter