Imma go through each of your points and see what I can make of them. Might not convince anyone, but fair enough.
- Jin Clan: If you think about it, it's kind of weird the guy joined the Ministry of Integrity as the apprentice of Cao Chun. The Inspector is supposed to be an utterly neutral and well-respected madlad. The kind of maverick who shows up on a Ducal House's doorstep to tell you, 'yes, you are under arrest. You broke the LAW'. That speaks to Jin Tae, that he might respect or even admire the ruthless pragmatism of Cao Chun. Further still, he's a Jin. If we take in the 'traditional' stance of all Jin, the guy should be snipping or at least trying to get some knowledge. In short, his talking up in that meeting without Cao Chun's permission speaks well of him. People aren't paintings; just because the majority of Jin Clansmen might believe in the 'usual' opposition to our efforts here doesn't mean we should paint all the Jin with the same brush. He'd make a pretty good sounding board too. Since he was raised among the Jin, he might know how to better frame things in our own efforts to get diplomacy going.
- Cai Reputation: In a way, not allowing people in to overlook things this late is sensible, and I won't disagree. There has been a lot of political power and favors bound up to make this work. Fair enough. BUT I would say we're... kind of screwed that way. Slow and steady works for things people actually want, or things that have alot of time to be implemented. By the standards of old hats like Cao Chun, Ling Qi and the gang are precocious kids getting into nonsense that'll probably blow up in their faces. I have little doubt plenty of our detractors believe the same. So why not flip the board?! Bringing in Jin Tae, last minute, means alot of things. If we make it work, then we're adaptable, flexible, capable and ruthlessly efficient in using every asset to further our goals. As the Bai might say, Victory is its own excuse. Not to mention, keeping on even those who might hate us, or at least disagree against our ideals, is pretty much how any committee is supposed to work. Someone has to play devil's advocate, or we'd end up with a crew of yes-men and sycophants like the Hui did.
Yes, Chao Chun is supposed to be neutral. But he's also really, really biased. So much so that we have to craft how we approach things so that he'd listen.l and agree.
Secondly, I'm not saying we should assume he's like every Jin, just that we don't know enough about him to really judge if we should spend tome with him this close to the summit. Remember, this is a long term project. If he's still our minder by then, we can get to know him more, but not when we're so close.
Secondly, again, he's not his clan, but his clan is against two of our strongest allies. And he's in the Ministry that's most likely to oppose us because of our philosophy. The Ministry that makes its members bind death spirits so that of they go against the rules, they're dead. If we had more info on the MoI from maybe Jiao, or more info about the Jin, maybe I'll agree, but we literally know nothing about him. It's a lesser degree of Zheng Fu.
Mind you, there's only a chance we'll convince him too. So, on top of all that, this is all for a chance to change his opinion last minute, when we have so many plates on the air, not enough action slots (remember, we'll most likely have to sacrifice two personal actions for professional), and no time. It can easily fail.
Plus, you know, alliances matter in the feudal society Destiny Cycle is in. He's in a clan that's against our allies. Even if we convince him, it won't be about us bringing the Jin over. It'll be about meeting imperial standards because, you know, he's just there to pass on info to Chao Chun.
And, I cannot stress this enough, if we actually do convince him and bring the Jin to the table...then we have a clan with interests against two of our allies.
We already have a lot of opposition *inside* our province. We don't have to deal with ones outside too when we can have a professional relationship that won't compromise us right now.
Edit: Also, from other perspectives, we have Renxiang, Gan, Meizhen, Xuan Shi, wjo, though they have similar ideals, bring lots of perspectives to the table. This is, first and foremost, our project