Okay because why not-

The war was basically because Felix had full reign over the body, Tyler went dormant for a bit because of how unstable everything was becoming in Jamey, Faz, and Felix's relationship.

So Felix gave Flaz a small portion of an army to command and control since Flaz wanted it. (Flaz and Mel were Felix's first kids so he spoilt them anyway and everyway he could)

Why did the war happen? Like I said Felix became basically unpredictable at that time as Tyler wasn't helping him be humane. It helped when he was around Jamey and Faz because well they are "human"  so he can kind of just copy them a bit?

The war was about gaining power, control, wealth- and just to show the world that he was capable of destroying anything and everything.

Basically the three in charge below were Flaz, Danny and Marshall.

Marshall took over when Felix wasn't there, often teased Flaz about being in a lower position.

Danny was pretty much the bodyguard for Flaz and Marshall. 

I'm gonna make it just one massive compound with several outposts for different people in command.

Yes Felix had child soldiers.

He had all different kinds of people there.

He fought anyone that opposed him.

It was pretty far from where everyone lived at the time- because of teleportation.

But he stopped because of what happened to Danny.

But Felix would 100% go to "work" again. He just wouldn't involve family this time.