So, the "failed" meeting place project isn't catastrophic, but it does put us in the back foot. If it had succeeded, we would likely had gotten a +1 bonus instead of a -1 malus.
Then we would have had the Emerald Seas Nobility at 6. That would have made any roll regarding them almost certain, as well as given us a good buffer in case we had to spend an allied faction's favorability to increase the more problematic faction's (MoI). We can still do it, but much more sparsely.
The Polar Theocracy would have been at 3, which would have given a good margin to negotiate with them. As it is now, we have to tread carefully with them least we lose further favorability and they fall to the negative.
This just proves that taking on the challange of the shared meeting hall construction was the right choice though, despite the unlucky result. All those benefits with a 80% chance was a sound risk, and the situation is still manageable.
Really, the worst part wil be that everyone we talk to will comment on how barebones the place is, many with a mocking attitude as well. That will be annoying.
I agree that gettig the MoI to +1 has to be the first priority. Not only for the summit final outcome, but because we are going to need their collaboration when we are investigating the sabotage. So we have to increase their favorability at the very start.
Trying to brush off the meeting place being incomplete will end badly. We overreached and paid the price, so we have to own the consequences.
Furthermore, creating a mutually recognized dispute settling system/institution is also one of our objectives for the summit, as adviced by Xuan Shi and requested by the Seared Lands. This approach puts the discussion in that direction.
[X] Focus the speech on how disputes, though inevitable, can be solved to everyone's satisfaction through words.