Two more aspects for disliking this deal:
A) We are not just snubbing Human Cults, we are also snubbing Elven Cults in their own home and blindly taking sides. I expect at least two Houses to care. Maybe more.
B) This whole Project is supposed to be about broad cooperation. One "race" whose inclusion in this might reach from helpful to vital is the gods themselves. Dedicating the Waystones to Hekarti specifically makes it quite a bit less likely that multiple gods will each do their part to make this whole thing work. And I don't think that Tindomiel will accept it as true to the contract if we say "Of course you can dedicate them to Hekarti. And these other priests will simultaneously dedicate them to Hoeth, Valaya, Thungni, the Widow, Taal, Verena, Ranald, Halétha, the Lady and a bunch of others."
I'm not sure how you get the idea that shrines in Laurelorn is a snub. It will grant them political influence in Laurelorn, which until recently was the limit of their world and remains the place where they live and will continue to live. And the heir is the only contributor being offered other than the head of the house that we can count on for political support, which I at least thought was the main reason we wanted Tindomiel in the first place.
EDIT: I don't think dedications are a snub either. Isthien seems aware of the attitudes towards magic in the Empire and will probably understand that some concessions need to be made.
A) "We support you to do whatever you want. As long as you don't do it where we live. Sure, have our backup in your own political pond that we know nothing about."
B) "Your specific request is that you get to honor your goddess? Okay. But only if you honor someone else instead. Or no one. That fits your request, right?"
Sure, both of those are still useful to Tindomiel. And can be coached with more diplomatic words. But we're talking about Elves here. The unflattering subtext will be clear as day to them.
I. actually don't know. Can anyone clarify how will Witch Hunters act if they encounter "Potentially harmless but not proven" situation?
In depth investigation is the correct way. Fanatics may do whatever. But they would be doing it illegally. And then an agent of the Empire's most powerful secret police would be in their rights to go snickersnack on their asses.
And if they can't build it for whatever reason—maybe they don't have the mages, or maybe the political consequence of building a shrine in Kislev is too high, they will turn down the contract and we will have to find and pay someone else to do the work—a group who have not been involved with the project since the beginning, and won't have the experience or knowledge Tindomiel have, and will have a mystery price attached to their work.
Two things.
First, right of first refusal doesn't mean they have to offer it for free each time. They could still demand reasonable rates and consider it a breach of contract if we refuse them and give it to someone else for a similar or higher price.
Second, if the representative of the Waystone Project and the representative of a Waystone buyer negotiate and the latter says "We want a Waystone, but not Tindomiel's (because of politics)", then according to this contract (if they are on land covered by it, the former's answer should be "I am sorry but those kinds of Waystones are the only ones we offer". Or more accurately, if Tindomiel has no objection themselves then we are not allowed to offer a different supplier. The only way to do it without breach of contract would be by either inundating Tindomiel with other requests and tacking the politically problematic ones at the back while also claiming urgency, or by using subterfuge to get Tindomiel to not want to work there without blaming us or the buyer.
P.S: I am using "buyer" here for ease of expression. I have no idea if the Waystone Project will be a public service supported by patron nations or if there will be some other kind of funding scheme.
That's what I see as a problem. What happens if Elves, for some reason will be blunt enough to ignore possible problems and willing to build Waystone in Kislev? And Kislev, at the same time, wants to build Waystone solely by its own power, using the knowledge that Ice Witch got while working on the Project with us. For prestige, religious reasons or anything else. I can't find imagine a good outcome for this. Either we choose sides, and have quarell with someone, or let them sort it out, and potentially start a conflict.
I know that this is not likely to happen. But there is a possibility.
If the Waystone Project never claims monopoly (which I for one very much don't want to do) then the Ice and Hag Witches would be allowed to build as many Waystones as they want, using all the knowledge that Zlata and Niedzwenka have learned. They'd even be allowed to get Dwarven help, as long as it isn't Thorek in person or his current apprentices (who haven't made journeyman yet).
The Waystone Project is, as of right now, not a permanent guild-like organization. It's a collaboration by independent agents and agencies, each openly holding loyalties beyond the Project itself.