one addition to yer advice on ammo.
They should get a semi-auto rifle also with a scope
and a thousand rounds to go with that as well as about five additional magazines that should be loaded with ammo ahead of time.
Same with the hand gun if they got one with a magazine and not a 38 special revolver type.
JMO but better to have plenty of ammo and plenty of firepower..
Also, self defense ammo (hollow points) for the handgun..
Lastly, get a big sign that reads: "Welcome to America" ya can show with several firearms drawn on it standing over either the corpse or badly wounded invader.