2 questions about open ports in comodo.

Hi, here are my questions:

Is it correct that only the programs that are allowed internet access in the application monitor, will be able to use an open port from the network monitor?

Would it be wrong just to make a rule allowing all ports in/out? (on TCP/UDP)
If no apps. are using the ports, all of them are stealth ?
Other firewalls opens the port when you accept incoming connection to the server once.
Creating this rule in comodo would make comodo act the same way?
Is that a bad idea?