Wow! That's some serious CSI level $%&* there.
Must be from the rifling marks right?

Couldn't resist.
If you can see the whites of their eyes, they're too close.
But seriously, review what you "need" not just what you'd like.
Do you need something that will reach out and touch something at 200-500 yards?
Will out to 200Y suffice?
Or is 50Y a long shot?
Do you need a high volume of fire? (Realistically if you do, you're in a mess and an air strike is more appropriate)
If the 200-500Y answer is yes, you need a full power rifle. The previously mentioned Rem 760 will do on the cheap as will most decent surplus bolt actions although slowly. CDNN had the Eagle polymer 10 rounders for $8 a piece for the short and long action 760's.
If the range might hit 200Y your'e good to go with the 7.62x39 AK round or the .223 in most situations. I'm still not a fan of either but for a cheap blaster, they'll do.
If 50Y is a ways out there, the scattergun and a mixture of 00 Buck and slugs will suffice.
I can stack slugs from a bead sighted 'riot' Ithaca 37 on a small coffee can at 25Y and can keep the larger ones rolling beyond 50Y. But I practice a lot.
Buckshot makes hitting somewhat easier and less dangerous to non-combatants at the short ranges.
There's almost nothing a good rifle can't handle. It may not be ideal but will generally perform yeoman service. When you need a rifle, you NEED a rifle. The others will not perform at the same levels.
However if I could pick up a .30-30 Marlin 336 used, preferably from a local 'oldster' I'd jump on it. The 4-5 round capacity doesn't hurt realistically. If I had to trim down to minimal, really minimal weapons it would be one of the last to go. Enough power to hunt with and not so much recoil to beat the shooter up. Most of these are high (carry) mileage and low round count guns that only need a good cleaning to bring back their factory luster inside.