Many of the recommendations are sound, the serrated edge Spyderco for example.
Why serrated? Because it’s a weapon and tool, the half serrated model and SAK give the user standard edges to use but the serrated edge cuts rope/belts like no straight edge can and will make a mess of flesh if it’s needed, that’s it’s purpose.

The AR/M4?
One can argue the choice over the AK platform all day and twice on Sundays.
But as it’s the standard US issue gun, and parts are more available than any other platform, it’s here to stay.
More people have been trained on it in this country in the last 50 years than any other gun.
One of my customers was in VietNam very early on, he remembered how to operate one perfectly nearly 40 years later, despite not having handled one since he left VietNam in ’66. (He still doesn’t like them)
Perfect? No, but it works and works well today.

LE reserve?
He is not incorrect, especially in the cities about LE officers being given a ‘pass’ when others would be stopped.
That includes Fire Dept guys. Sorry but FD guys aren’t cops, I see one with a gun, I’m gonna suspect something’s wrong with him. LE guys may not always recognize each other, but that badge/jacket/raid gear is a sign of brotherhood and trust. Something goes sideways, I still have my old badge, tac vest, jacket and other gear, and the local Sheriff’s guys all know me. Worst part? I’d likely be dragged into the SO and given a new badge and expected to work.

The common handgun?
Realistically it’s whats the most common not just in the military and LE, but in everybody else’s hands also.
Glock has 65% of the LE market, and heaven only knows how many are in private hands, they are everywhere.
Beretta? Besides being the .mil gun, with every soldier in the last 25+ years being trained on it, but for years they were extremely popular and common in private hands. A customer just brought a brand new one in two weeks back, they are still a good choice after all these years. And the 92 is still an ‘issue’ choice for LAPD officers hence it still being a good choice for those in that area.
The night sights? Especially on the Glock? Because until recently the Glock sights were not just cheap plastic, but cruddy cheap plastic, the front sight easily knocked out of the slide. The steel night sights are much stronger and durable, the night feature are a bonus.
And while I prefer a different handgun and caliber than the Glock/Beretta 9mm/.40 options, I can say that they are not a bad choice, especially for this purpose.
My first duty gun was a Beretta (96 .40cal) and I still have a soft spot for the Beretta 92 family.

Downplaying the .308? Again, location is the key.
He’s not expecting to deal with an angered Moose but soft skinned gang bangers and their cars/cover.
I can understand his choice, even if it’s not mine.
But looking at ranges, targets and such, the .308 is a great cartridge (and my personal choice) but for most shooters, especially for this situation, it’s too much of a good thing. Especially when fast second shots are needed from a manually operated gun.

Ammo from others? Tough call.
LE will possibly give another LEO ammo/mags in an emergency.
During Katrina, a number of LEO’s had to be issued ammo because their gear had gotten soaked, gotten left behind or their ammo lockers fully swamped and unavailable.
Most of us carried a spare box of pistol ammo in our “war bag”. If it came to it, I’d have handed that box to a fellow blue-suiter in need. Someone else? Unless I knew them, ain’t gonna happen.
Just don’t expect to get that ammo if you ain’t got a badge.
As a private citizen? I’m keeping my ammo in a bad situation, and I don’t expect to be able to gather any more for a while after it hits the fan, if ever.
In this situation, the guns/ammo is purely defensive not offensive. If it were offensive, there’d be a great deal more of it. This is to break contact and get home.