Raever culture question

So I created a Ratfolk, raever chaos-materialist empire what I wanted to bring in multiplayer. Looked up some guides but they always saying they can't be diplomats and can't form relationships. I know they has the Total War trait and starts with zero whispering stones in normal conditions. But if I get them one stone with the empire development tree can I make free cities like me? Or the total war trait is a bad sign for the AI and I get penalities because of it? I not seen any statement of this on that trait. So why is that?

My idea is:

• I befriend with one or more free cities. I need suggestion how to get at least two whispering stones.
• Probably I want 1-2 Ai alliances. It is possible?
• For war spoils I want to take care 1 empire, maybe two with my friend (idk what culture or path he is chosen).
• Spawnkin is a good idea for the reavers? It's a dmg buff and I want to pick up constructs for melee so they can't get affected by the negatives of spawnkin. Can I make them to mark enemies with them for my rifles?
• Pyromancy for the mage units! I find them pretty useful in the raever army.

Aaand my biggest fear with the Reavers: How to get knowledge with them? I played last night a trial run and found out they get behind in the research. My current tome focus is chaos and materialist. Chaos can gain a development when I kill heroes I get knowledge in return. Sounds good, but that's enough?

Last time I played an Order Dragon Lord build with feudal monarchy. I found them strong, but the Reavers seems to start slower and without proper support/healer spells and units hard to keep alive the maglocks.

We planned play at tonight so with the suggestions I can tailor my plan out better and I can get a better understanding with this culture.