I'm thinking things in 21-V's plan (which is heavily reworked) should make appearances during the Cairn's Council and help lead to them kicking Barrett out.
Barrett's central motivation stuff (the last paragraph of 4-B mostly). I'm thinking he respects Lord Hayden's ability to unify those without a home of their own (tying into his dryadic parents story) and wants to use the gryphter's wealth to strengthen those ties. He'd be aware of the constant infighting as well. This would fix this vignette and then make an appearance later on when he starts to think about becoming Lord Barrett -- particularly in how Lord Hayden's mistake here would upset the unity he had worked so hard to achieve. With wealth, there could be lower-risk training as well.
With the MOAB fixes completed, alter Myrddin and Olivia's vignettes beforehand to (very subtly) foreshadow these events. And I guess merge them too into whatever they were thinking about before (Dilan and family respectively, iirc). Also add a touch of dramatic irony -- their plans after they do this (which they can't do as the plot twist kills them).
And I don't like that they're going to Olivia's family's side of the world with that plot thread just being dropped when Aety becomes a Spriggan. Probably just needs more interiority on a third pass of MOAB. Or I could drop it if that doesn't work out -- it's only one sentence said by Myrddin, after all.
