I didn't see anything mentioned about radio communications, other than the radio stack in the aircraft. For the choppers kit you might add 3 or 4 FRS/GMRS radios with spare batteries.
Those are idiot proof and can keep a group connected if someone ventures off.

In my airplane I carried a heavy duty prescription pain medication in my kit. Back then it was Dilaudid, but there may be better ones now. There are sometimes horrific injuries and burns in a crash and pain management can keep people alive.

A good compass and whistle.

One last thing I sometimes carry that might sound strange, is a pocket parafoil kite. I like to fly kites but if I'm stranded and I'm able, that sucker is going up. It's tiny but you can see it for miles above the trees, assuming you have wind.