A resounding "NO!" to the first part. The Army medevac birds with the big red cross are exclusively medevac birds and go unarmed and I'm guessing a little afraid counting on that big red cross to protect them (that and an escort sometimes) too bad this is a throw back to days of civilized enemies instead of the barbarians we have found ourselves fighting of late. Marine assault support platforms do perform medevacs but they do so armed and as one of many missions they stand ready to perform.
We set up our Helos in squadrons vice cmpanies and battalions fo the army. Personal opinion-squadrons allow for a more fraternal feeling and a little more individuality. Not opinion-A squadron allows for (though not always followed) for experience to lead vice rank. In an Army unit that commander is always leading the flights unfortunately he is usually the lowest hour guy in the flight(BAD IDEA) whereas in a Marine squadron the majors and senior captains are (usually-there are some paper tiger majors running around)the most experienced aviators and they lead the flights.
Hope this helped.