Here is Vern's assessment of the Speakers and other factions on Corax:

Of Corax history: You've already been over this, but there are a few additional items worth nothing. The planet was terraformed and later settled during the Dark Age of Technology. A great disaster took place during the age of Strife, destroying much of the planet and most of its hives.

But human life endured somehow, despite hellish conditions. The people grew short and wiry - the evolved into ratlings, as happened on other isolated and devastated hive world during the Age of Strife.

Yet on Corax something miraculous happened; they not only survived, but eventually prospered as the descendants of the survivors found their Paradise - Hive Primus, virtually intact in all its dark technological glory. And somehow, against all reason the survivors managed to cling on to at least part of the tech-lore of old, enough to keep the hive running century after century after century...

Up until M39, when visitors arrived...the aforementioned men fleering the advance of the Imperium (in the form of the Angevin Crusade that eventually led to the creation of the Calixis Sector - officially made a sector in 384.M39). These warriors from the stars took what they wanted and nearly drove the indigens to extinction, pushing them into the unused and dark lower levels...

...that is, until the hive started failing and the Founding Fathers ralized they needed the little ones. And so a deal was  offered. The ratlings would be allowed to live in the lowest, least desirable portions of the hive, and in return they would take care of systems the invaders had no hope of ever mastering. It was an unfair deal, but better than destruction...and so the situation remains.

Of later arrivals: As is revealed further below; a second group has settled on Corax, arriving in M41. And there is still no explanation as to why parts of Corax' population holds faith in the Emperor, while so many do not. Unfortunately there are no records of those times - they may well intentionally have been destroyed.

A final note on the Speaker's Houses. They really have very few ties to the original Founding Fathers; the Johammod's for example, arrived very late and are not related at all to the original Fathers. And some of the current Speaker clans have risen from obscurity, while others have fallen along the way - of those present now Xolix is definitely Old Blood,  with the others having varying pedigrees.

The settlers: The settlers is a non-homogenous group that have carved an existence out of Corax' wilderness and who want as little to do with the hiver as possible. Of course, with the war and all many have been forced to abandon their homesteads and seek refuge beneath the earth.

The current First Speaker is one Madame Eoila Xolix: Eolia is a tall and dry old hag that seems far too full of herself. Or maybe she's entitled to some air, being a sovereign ruler, free of any Imperial constraints?

Xolix took over five years ago following First Speaker Mario Holt's death. Her ascent involved the usual amount of violence, intrigue, and bribery. Besides the First Speaker have most often come from the ranks of the Holts and the Xolixs (especially that case these past five hundred years); a result of their control of hive utilities and archaotech reclamation respectively.

Xolix has control over some manufacturing assets and secondary hive utilities, but her prime power base is hive reclamation. That means stripping Corax' other hives of valuable stuff. Well, most of it isn't all that valuable, having been made countless millennia ago, but here and there useful items can be found.

Now she also has the support 'someone else'. And these people (or xenos?) have voidships, which could give her control of the whole reclamation chain from procurement to final sale. And the backing of a potent military force.

That might not have been enough to really scare the other speakers, had it not been for what she's intending to use that power for - to reform Corax' society, which in her mind is long overdue. Such as giving the ratlings and the free-steaders each a place on the Speaker's council. Radical stuff to say the least!

Vern's assessment is that she wants to preserve Corax, and genuinely thinks her way is the right path to follow. She doesn't want to destroy the other Speakers' Houses, just redistribute power a little - to the benefit of 'the people' (whatever that means).

At any rate the other six Speakers are probably no better:

The obese Frau Temera Hauptish: Hauptish is the only Speaker who is really interested in bringing Corax into the Imperial fold. Both because her clan believes in the God-Emperor and humanity's manifest destiny, and because they think that the planet would do well under Imperial rule. They control much of Corax industry through various tech-guilds, so they stand to gain a lot of income and power if they gained access to some new markets. Her secondary power base is with the Faithfull of Corax (i.e. those that worship the God-Emperor).

Hauptish has been in contact with Soldevan several times, but she's afraid to court him openly, as doing so would announce her intentions and make her a target of reprisals from the more independent-minded Speakers.

The positively ancient (and heavily augmented) General-Oberst Erik Brüller: Is the man in charge of the militia. He's a pompous ass that is largely ignorant of the deeper wheeling and dealings. He sees the ork attack as an opportunity to prove himself and gain some much-deserved credit from his peers. Beyond that he's not really a big political player. His traditionalist views are well known; he supports the oligarchy, doesn't like the people settling beyond the control of Hive Primus, and doesn't want the Imperium to get involved. By and large he supports the sitting First Speaker as long as he doesn't make waves or appear too progressive-minded (which the current one does, so he's no longer adamant in his support).

The stern-faced Charles de Motaguinne: The leader of the financial sector (such as there is - its less like banking and more like a loan-shark operation) de Motaguinne is a rising star in Hive politics thanks to his affair with the poor Holt widow (its a well-known fact that she's traded away much of her freedom and power in return for short-term protection for herself). He's also sort of an underworld overlord, but one that very rarely involves himself directly into the affairs of lesser criminals (he's just content to skim the profits and uses his House Regulars to spread fear). Charles is also the Speaker with the most ties off-world - ties that he maintains through personal contracts with several minor rogue traders. He's not anti-Imperium as such, he just thinks there are more opportunities for Corax (read: himself) as a rogue planet.

The almost painfully handsome Marshal Bill Tricker: Head of Hive primus security/police force. This local Enforcer cadre is typical of such organizations; corruption is widespread (but not completely out of control) and incompetence is rife (although there are certainly exceptions - Special Branch looks competent enough as sectret/terror police goes). He's mostly just concerned with maintaining the status quo and his own family's power (which generally means cooperating with de Motaguinne, at least for the moment).

He's a real asshole, but can probably (Vern's estimate, backed by Xerza's readings) be convinced to provide aid if he thinks Hive Primus is in genuine jeopardy - not out of alturism, but out of self-preservation. He might even agree to join the Imperium as long as he'd retain power (or even better, gain some more).

The barely-adult Kimberly Holt: The second wife of First Speaker Mario Holt is a former courtesan turned trophy wife turned powerful noblewoman. If she hadn't been a shrewd mother she'd been dead and buried long time ago (right after Mario's death five years ago), but by selling out to Charles de Motaguinne she's secured her own position for now. Being childless there are always Holt scions ready to take over should she 'falter', but Kimberly deftly deflects such notions by implying that she'll marry any male Holt that rises to the occasion. It is generally believed that Kimberly is an off-worlder.

The Holts have controlling interests in Hive maintenance; including taking care of the age-old 'treaty' with the ratlings. The smooth running of the hive and its ancient systems is of course of paramount importance, and hence the Holts are traditionally very influential. The existence of the ratlings is known only to a very few (beyond the age-old rumors of 'things' in the walls etc.) - the Speakers and a few others.

The positively alien-looking Ibhram Johammod: Leader of the voidborn faction that descends from Meritech clan refugees fleeing the destruction of their movement. They arrived in the Corax system in the late 3rd century M41, finally finding a new home here.

Over the following centuries they slowly established contact with Imperial space, selling plundered archaotech in return for luxuries and other foreign goods (where there are more than enough rogue elements willing to trade with them). Before the arrival of the voidborn Corax had no real contact with the Imperium - so it all sort of started with them.

Johammod doesn't like the new Protasian 'allies' at all since the undermine his powerbase. Normally wary of de Motaguinne, he is feeling pushed into his corner by the First Speaker's recent actions. He hates the Imperium for what they did to his ancestors.