Do you think that the various organizations in Braavos, such as the Sealord, the Iron Bank and the Faceless Men, share intentions and ideals? If so, what that would mean for the theory that the Faceless Men want to destroy all dragons and the fact that the previous Sealord was a witness to the marriage contract between Viserys and Arianne?

No, I don’t, and I think people make a huge mistake when they assume this is the case. The Iron Bank of Braavos is an explicitly capitalist enterprise, the Faceless Men aren’t that keen on wealthy people abusing the poor – the Iron Bank would need to be facing an existential threat to be willing to pay what the Faceless Men would consider a suitably sincere sacrifice to the Many-Faced God. A similar thing would apply to the Sealord.

Likewise, the Sealord and the Iron Bank have similar but not identical interests – the Sealord will support the Iron Bank to the extent that the Iron Bank is good for Braavos’ economy, and to the extent that the Iron Bank’s keyholders supported him in the last election, but there’s a reason the Iron Bank prefers to hire mercenaries rather than use the Braavosi military, because you don’t shit where you eat. Likewise, the Iron Bank will extend credit to the Sealord where it’ll make a profit and/or protect their significant interests in Braavos itself, but not on a risky foreign adventure.

Rather, I think we should see these institutions as independent, while recognizing that they will always band together in a crisis.