Without reading through your code...you can create a bunch of cameras then show/hide the ones you're interested in or not.
If you want a smaller camera viewport rendered over your main camera do something like
This will render your main scene then render your extra cam afterwards (ie overlay it) then flip the backbuffer.
Also look at using the {codebox}{/codebox} tags (with [] instead of {}) to maintain your code formatting. The code you've posted looks horrible due to lack of indenting.
If you want a smaller camera viewport rendered over your main camera do something like
hideentity littlecam showentity maincam renderworld showentity littlecam hideentity maincam renderworld flip
This will render your main scene then render your extra cam afterwards (ie overlay it) then flip the backbuffer.
Also look at using the {codebox}{/codebox} tags (with [] instead of {}) to maintain your code formatting. The code you've posted looks horrible due to lack of indenting.