I've killed a deer with 223. It was just as dead as the ones I've killed with 30-06 and it didn't run as far as some. But I have better choices so I don't use it as a rule. ...,
I've hunted deer, mostly in thick brush for over 40 years. The secret is a very accurate rifle with a laser flat trajectory to 100 yards and good low light optics to be able to see tiny openings in brush and put the bullet through it. The traditional lever guns, and cartridges for them aren't accurate enough, nor do they shoot flat enough even at close range to thread shots through those openings. There is no such thing as brush busting bullets and rapid fire repeat shots are far less important than 1st shot precision. Even at close range.
I agree, except, I'm not certain how the OP is going to hunt.
For deer, it's correct that one wants a very straight shooting round if going after them in heavy brush, and make that first shot count. I too have hunted deer in heavy brush for decades, using a 225 lead round ball from a flintlock, and because of that trajectory, I'm more limited and I need a clear shot...no "threading of the needle" for that type of bullet.
I think that most of the platforms in the post will work for a clear, single shot, and humanely harvest the deer, but going into a dense brush situation, the flat trajectory is a must.
Hogs
might different..., So I opted for the 7.62x39mm rifle because of the hogs.
BUT...., If I was the OP, I'd get an upper for that round for my AR-15 instead of a Ruger Mini-30, especially if I was going to use an AR-15 based "pistol".
IF the OP is simply going to hunt a single hog around a bait pile, or maybe a pair, then again most of those choices work fine, but IF he's going out to eliminate a bunch of hogs, planning on keeping a big one for eatin'..., then he's going to need a semi-auto. Since he's also considering a very short barrel, the 7.62x39mm is (imho) better than the .223 Remington due to bullet weight since shot placement will be a bit more "iffy" on all but the first hog when the shooting starts. A heavier recoil spring and heavier buffer and the recoil won't be a factor
Besides it's more fun if you have uppers for you AR in different cartridges
LD