1. A good general run-down on the rise and fall of chariots.
Of note for your purposes:
* they were mostly two-man arrangements
* they were in decline during your period due to the rise of iron weaponry and improved infantry tactics although this would not have been obvious to most people of those times
* they were still prestige transportation; they were expensive to build and maintain, so only used by the elites.
* they were level-ground weapons, later to be replaced by the horse and cavalry tactics
2. Another good general piece that confirms the two wheeled chariot was most often used b/c it was more maneuverable in rough terrain.
And then there’s this:
The two-wheeled version soon proved superior in battle because of its higher maneuverability. Greater speed was attained by the use of teams of two or four onagers and by the evolution of the light, spoked wheel. The introduction of the horse as a draft animal in about 2000 bc was the final step in the development of the chariot into a military arm that revolutionized warfare in the ancient world by providing armies with unprecedented mobility.
An onager is a close relative of a horse. Think Asian steppe zebra and you’re close enough.
(The one of most use to you will be the one detailing the Assyrian chariots and their use. The Omirides were cheek by jowl with them and would have known most of their technology.)
3. This one is specific to Assyrian chariotry, but very useful for your purposes. There’s a lot of detailed discussion about types and uses that will help you out. Do note however that when thinking about what the Assyrians were doing vs the Israelites, you have to make some allowances. The Assyrians would have conducted a great deal of their conquests on open plains where the chariot would have been highly effective. The smaller buffer kingdoms like Aram, Moab, Judah and the Northern Kingdom would have copied them to a large extent.
That said, you can safely use the vehicles depicted here as models for your own guys to use. Note that the first one is hauling four guys in one single-axel chariot, so there’s the answer to the question that started this.
I think if you take this discussion and modify it for the fact that the Levantine kingdoms were generally dealing with more hilly terrain, you can put your people in chariots where you know they’re traveling on mainly flat or rolling ground. They can’t loll around in chariots or sleep in them the way they could in carts, but Ahab and O could travel together in one when necessary.