This whole project was the Eonir's idea originally, and they specifically framed it as working with K8P. I think it's fair to treat their participation as a lock as well, regardless of whether they get to run the whole show. The tricky part with the Eonir won't be getting them to participate, it will be getting the dwarves to be enthusiastic/at least not recalcitrant about working with elgi, exemption from War of Vengeance bad feelings notwithstanding. And the dwarves will be a lot more likely to be comfortable with that if it's under the dwarves' control, or at least not directly under the elves.
I mean, don't get me wrong, I actually voted for Laurelorn at this stage myself. But I don't think it's correct to treat the Eonir's participation in the project as iffy and in need of convincing when they're literally the only party we already have a hard confirmation that they want to do this, nor do I believe it correct to suppose that dwarven buy-in can't meaningfully vary depending on options selected. You're not wrong that Algard does seem clearly on board, but he doesn't have the power to speak for the Colleges as a whole and the most likely relevant sources of expertise on Waystones in the Colleges are the Jades and Lights, not the Greys. And Belegar himself will back us up pretty near no matter what - but again, he's not in charge of all dwarves by a long shot