Unless you can read ancient Egyptian, Greek or some such, you'll definitely want secondary sources.
Osprey:
- The World of Celtic Warrior
- New Kingdom of Egypt
- Bronze Age War Chariots
- Hittite Warrior
- Ancient Chinese Armies (specifically the chapter on Chou)
For translated primary sources, there is Illiad, but that one has combat by champion almost exclusively, even if they do use chariots.
Very, very poorly. The chariots as taxis, where you dismount before the battle, is somewhat more viable, but in an attacking formation... The issue is that rough terrain forces you to pick your path in a chariot, so it funnels all your formation into predictable, narrow paths they can't turn away from - and if one of them gets mobility-killed in them, you have a crash and a traffic jam on your hands. What's worse, if you are in a climate that looks like most of Europe, you will also have relatively soft soil do deal with - one chariot may make it, but a dozen in the same track will have a problem.
Also remember that you cannot stop in range of the enemy, or their archers will shoot you to pieces.
The advantage of chariots is speed, so anything that can't keep up is right out. That limits you to chariot only units, or chariot and cavalry mix (Persians come to mind, with using their scythed chariots to break up enemy formation, with cavalry for follow-up). Well, provided there are enough chariots, otherwise you use them as mobile command platform.
As for how many, well, how many do yo have? Ancient Egypt reports armies with about a thousand chariots per side being fairly common, and battle of Kadesh saw as many as 2 000-10 000, depending on who's counting.
Horses can number from one to ten, with one or two being the norm - and they were armored as often as not.
Occupants number from one to three, with one handling the reins. If there are two, as is the most typical, then the other person has a bow, a spear or both, if there are three, the third guy usually has a large shield.
You kind of answered your own question there: Illiad. Aside from that, there are Celtic war chiefs who fought this way, and frankly, any chariot will do this in bad enough terrain.
This is pretty much all societies - chariots are even more expensive to use and maintain per unit (and sometimes per man) than cavalry.
As for the actual question, I can't really answer it without doing several hours of crawling through sources. Egyptian charioteers seemed to have been fairly equal in status between driver and fighter, but this will vary depending on time and place - Celtic war chiefs were, well, war chiefs, so all other crew of their chariot were less in statu
The only major thing I can think of is more emphasis on cooperation - you have two people per chariot, they need to work together even more than two cavalrymen. Going into fantasy land, wife and husband teams are possible, as well as some sort of shared families, stemming from this only.
It's mostly bad, not gonna lie. Less agile, about as fast, unable to cope with rough terrain, chariot isn't a great vehicle. It's also unbelievably expensive, just about the only cavalry type that can cost more is the superheavy cavalry (thing all-plate armor on horse and rider, or Cataphracts), and even that is probably slightly cheaper than heavy chariots.
The sole advantage of chariots is that the riders are harder to hit - they are in cover, provided by their horses, and even if you shoot the horse, it will not usually fall straight down and crash the thing, it will start to slow down and die.
Depends on the chariot. The number one method is archery and throwing spears into the enemy flanks and rear while they engage your infantry. The enemy infantry know this is a death sentence, so they will often simply run from you should you beat their chariots. Failing that, you ride alongside whatever you don't like and poke at it with spear (be prepared to let go of it, lest you be clotheslined if it gets stuck) or use your scythes to damage it.
Running straight into formations is not exaclty recommended. You will trample down most infantry, but are liable to take losses - and something like a phalanx will just chew you up. Running straight into another chariot will kill all of you, running into a cavalryman will maybe not kill all of you, but will definitely damage you enough to take you out of a fight.
Your worst enemy is, aside from other chariots, archers - if they have enough time, they will shoot your horses down and mobility-kill you, if nothing else. On the other hand, you know this and go fast, so you will do your best to eliminate them first thing after dealing with enemy chariots - and archers are unlikely to hold ground against you, so this is one place where you can actually just trample them.
Edit: I really screwed up the formatting on this one.