In need of severe network help.

I live about five miles from my city so kind of rural. Im paying for a 50down/5up connection.

I mostly game and stream and my parents stream.

When gaming my NAT is moderate. I open my ports but my parents are paranoid it will let intruders in.

We have 5 desktops, 2 laptops, 2 ipads, 3 iphones, etc all on this connection.

I used to be able to game and stream simultaneously with no problem, now i have constant lagging and freezing.

Im using a Motorola Surfboard and Apple Airport Extreme Router.

Can anyone give me tips or steps to help my connection?

anything is appreciated, thanks!