Can you bring outside food into the sirport

Yep, up until security.

Yes you can.

You can, but you have to consume it before going through the security checkpoint.

You are permitted

You can but you will have to throw it away at the checkpoint .. so you should buy snacks or food there

Yes I also bring snacks and stuff to munch on during the flight

Yes

If it is in small amount and in a manufactured package.