The general consensus of the community is that the bots are all programmed the same. However, if you watch them more closely, you will notice that this is not the case. While I have only 170 hours of the game at the time of writing this, the majority of them are pretty much spent on testing each bot with all of the weapons and team comp, and I can absolutely say that there are differences between them. While most of the stats I saw are of Left 4 Bots 2, remember that it is just vanilla AI being enhanced, so outside of a drop in accuracy and damage, their general behaviors are the same (I testify that I already observed these differences before I installed the add-on). The purpose of this guide is to show you their traits so you can build your team with this add-on or just have some fun knowledge about your buddies. Before we start, I can only tell you the general stats for each section because they will obviously be different depending on what type of map you play and your luck. A particular survivor may have a bad day and show lower stats. It is what they are consistently at that affects my ranking.

(+) They often reach above this value
(~) They are usually around this value
(-) Result from 3 tests or less (less reliable)

Depending on luck, the range of accuracy score is usually + and - 10% of the number shown.

Riffle:
Ellis (+40%)
Zoey(+40%)
Louis(~40%)
Bill (~35%)
Rochelle (~30%)
Nick (~30%)
Coach (-29%)
Francis (-28%)

Shotgun:
Francis (~72%) *highest recorded is 92%
Louis (~69%)
Coach (~60%)
Ellis (~56%)
Nick (~51%)
Bill (~46%)
Zoey (-46%)
Rochelle (-43%)

Sniper:
Ellis (+50%)
Zoey (+50%)
Bill (~50%)
Louis (~48%)
Coach (~46%)
Nick (~45%)
Rochelle (~44%)
Francis (-42%)

Magnum:
Ellis (~76%)
Louis (~68%)
Zoey (~62%)
Nick (~51%)
Coach (~50%)
Rochelle (~50%)
Bill (~56%; however, he rarely pulls out, so I'm dropping him)
Francis (~36%)

Double Pistols:
Coach (~56%)
Bill (~52%)
Ellis (~50%)
Zoey (~50%)
The rest are the same (generally stay below 50%)

Melee:
Since accuracy does not track melee, I rank them based on how often they use them and how good their skill is. There seems to be a difference in proficiency between each melee too! Like Francis is able to use Riotshield and Crowbar well when others sucks with them, and Nick is better than others with a knife. However, we will treat them as one group. Please also notice that the manual attack setting probably helps a lot here.

Francis (MVP Melee God)
Zoey (Gets hit rarely)
Rochelle (Precise)
Nick (Reliable)
Ellis (Bad reaction time)
Louis (Somehow miss them)
Bill (Decent but never pull out unless out of primary ammo)
Coach (Very bad reaction time)

So, now that we know that your weapon preference setting does matter, what is the best setting? Well, the default setting is already good, but if you want more details, continue reading. As a general guideline, you want at least 1 shot gunner in your team. Riffle can be used in any range. While snipers are often regarded as bad, they are more useful in higher difficulty. Having one sniper (Not the CS snipers) on your team and properly supporting them will make your game easier than you thought. Though the manual attack skill setting needed to change to 2, the attack radius needed to be raised to fully utilize this. You also want to keep different types of weapons rather than using the same weapon again and again. Each Tier 2 Weapon has its own role, and the more you have, the better.
In terms of primary, I recommend three possible team comps:
A: 1 Shotgun, 3 Riffle (Too Tired, No Thinking)
B: 1 Shotgun, 2 Riffle, 1 Sniper (Better vs. SIs)
C: 2 Shotgun, 1 Riffle, 1 Sniper (Better vs. Common)
For secondary, you want at least two melee people in your team, especially for custom maps. When a horde or a panic event is going on, a pistol is poor at dealing with them, and I would argue that instead of saving that magnum for incapped, why not prevent yourself from getting incapped in the first place? Having melees is literally what allows me to clear maps with a ton of infected like Buried Deep, Blight Path, and Wan Li. Heck, even Dead Air and Dark Carnival were easier, thanks to them.
For the other two, there is not really much choice. Coach and Bill only use double pistols well and often, so they are stuck with them. The best magnum users are Ellis and Louis, so that leaves us with the only one possible teamcomp for each group.

And hilariously, that is literally the default setting, so if you have not changed the weapon preference file, you are already set.
In case you are using other mods to change the weapon preferences, here are the teamcomp:

L4D1
Bill- Riffle, Double Pistols
Francis- Shotgun, Melee
Louis- Shotgun, Magnum
Zoey- Sniper, Melee

L4D2
Coach- Shotgun, Double Pistols
Ellis- Sniper, Magnum
Nick- Riffle, Melee
Rochelle- Riffle, Melee

Before we end, here is a meme comp:
If you set manual_attack_dual_pistol_nerf = 0, then remove every weapon except the pistols. It becomes an unlimited machine gun, pretty much. Please send me a video of your run if you do.

If you have a question or a different result, feel free to comment and contribute.

Testing parameters:
Co-op game (no mutation)
Campaigns: Dark Carnival, Hard Rain, Parish, No Mercy, Crash Course, Dead Air
With human player presence (No all-bot game)
SMG and M60 are treated as Rifle
Bot always Lead
Left4Bots2 setting is a combination of LimmyTastic and NasCoz setting