It's not like Riombara knew about their intentions and decided to go out of their way to give them a home knowing what they were up to. That is just silly. Here is the explanation:
And about the Nobles that seceded:
What happened was that Marec was Ruler of IVF and he turned against Guillaume when he learned of his Agreement with the Daimons. He then joined Riombara when the Daimons besieged IVF to continue the fight, where Guillaume then angrily left for Enweil. That IVF under Marec is what Riombara is recreating, because IVF distanced themselves from Guillaume in the end when they learned the truth, which was enough for Riombara to accept.
Yes you did. Everyone knew that. The accord between KoA and the monsters was very public, everyone knew that they were going to form a colony to serve the monsters after ceding (losing) Eno to the monsters. They went to Riombara for the specific goal of founding Meridian Republic.
And IVF was flipped into Enweil first, killing the realm, and then Marec, as duke, flipped his duchy to Riombara.
Poll