You're losing sight of a basic issue while you trifle with doomsday fantasy. A massive breakdown of social order is less likely than a real burglar or just being confronted by a creep with a personal grudge.
I think your first gun needs to be a stainless steel .38 or .357 revolver on a medium frame, with a four-inch barrel. I'd limit brands to Ruger or S&W. Learn how to buy a used gun safely. There are a lot of police trade-ins, and stainless finishes can be polished out if minor scuffs are present.
You can have this at bedside or on you when a long gun can't be present, and it is ample for most needs, once you learn to use it well. It is harder for an intruder to take from you than a long gun.
Next, you can add a good used Remington M-870 in 12 or 20 gauge. Just racking the slide on that will cause many vermin to run. Just buy a basic hunting gun, not a tricked-out "tacitical" model. But do get a good used Wingmaster, not the economy grade, which has cheaper parts and workmanship. A 26" barrel is handier than 28", and older ones have a more open choke, better for your needs. If you have the option of changeable choke tubes, install the Improved Cylinder one.
If you want a .22 rifle, try a Marlin M-795SS. It has a stainless barrel and is often more accurate out of the box than a 10-22. Marlin owners seldom seem to need to alter them much. I just added a sling. Bought a spare box magazine. I paid under $150 new in 2004. (Used .22 autoloaders are often gunked up due to lack of proper cleaning.)
These three basic guns will stand you in good stead until you have more money and sense of what you want. I do not think a Moisin-Nagant or other foreign military rifle is a good is a good idea. if the fur does hit the fan, you want your rifle to chamber .308 or .30/06 or .223. Think ammo supply. And those make excellent hunting cartridges, with a wide choice in ammo.
You can use a 9mm pistol in lieu of the stainless revolver I recommend, but it'll cost more for a good one, and you seem to lack experience with firearms. A revolver is safer to learn on. And it is more reliable in AVERAGE hands.
Buying a cheap brand like Hi-Point is just wasting money and the gun will probably be hard to sell after you realize that you wanted something better. If you have $400-500, get that revolver first. Then, save for the others. Actually, $500 may well buy a good used revolver AND that Marlin .22.