Staredown: While yes it it certainly possible to bluff your way through the Bloodlines Mission via Stats, Etiquette and Dialogue, though it does require a significant investment in the dump-stat-if-you're-not-a-Shaman-(or-an-elf-I-suppose) Charisma, the question, at least as I interpret it, was 'Can I sneak Metal Gear/Tenchu/Alpha Protocol/Republique style by dodging the guards/cameras/enemies sightlines without the rest of my team giving me away?'
And the answer is 'Technically yes, but practically it requires a lot of savescumming. A. Lot. Of savescumming.' That's why I say the stealth system is inelegant, because the game heavily implies that this is a valid way to be remain undetected (and if you were alone, or able to move one runner at a time, it would totally be viable), with the guards not reacting to you when you're behind them until you're very close. But realistically, since you can't, no it's really not.
I think your quotation there explains what the OP was asking. A lot of other posts in this thread are assuming the player will have the correct stats to make the disguises work via conversations, and the strategies they give to solve the OP's problem require the player to have those stats. But maybe they don't.
I found this thread today via a Google search because I had the same question as the OP. Through no fault of my own, I got stuck being unable to retain my stealth on the Bloodlines mission. I shut down the power and went into the building through the side entrance. I found and put on the security guard uniforms. But even with disguises on, all the real guards who stand in unavoidable locations (i.e. the elevator room) still see me no matter what I do. And they ask for ID even though I have a security uniform on. And then they attack me because I don't have any ID. That is quite unfair, given the fact that the the game gives me no possibility to acquire any ID.
Therefore, the security uniform is a completely useless disguise if you don't happen to have a character with the exactly "correct" stats to make the disguise work with dialogue choices. IMO that's bad game design because it breaks the ability to solve the mission properly for many players, and it penalizes players who built their characters in a way that doesn't happen to correspond to the mission's random & unreasonable stat demands.
To avoid that problem, the developers either should have:
1. Made the disguises work for everyone who wears them regardless of character stats (entering the building through a special entrance and finding the disguises while being undetected already amounts to more than enough effort to reward the player with a disguise that works on its own).
or
2. Include in the game a mission item called "security ID" so that characters who don't happen to have the stats that the mission randomly demands can still solve it with stealth anyway.
I am not sure that your point is correct when you say that "technically yes" the mission can be solved in the proper way with the "incorrect" stats through savescumming. I spent an hour reloading saved games to try to sneak past the guard who is in the elevator room. As far as I can tell, it is simply impossible. I assert that the elevator cannot be reached without him seeing you (but I could be wrong about that). Even if it is somehow possible, then it is probably beyond the capability of an average gamer to figure out, which would leave it effectively impossible for most players (which means it is a major problem that needs to be fixed via a patch).
But how do you know it is technically possible? Have you done it? Or were you just assuming it is technically possible...but maybe it's really not?
This is important to figure out with 100% certainty because I am sure other players who encounter this game-breaking problem will search for a solution via Google and then find this thread, just like I did. They are going to want to know the same thing I wanted to know: is it technically possible to sneak past the guards if you chose the "wrong" stats? And if the answer is yes, then how is that done, exactly? ....Alternatively, is this an inherent defect in the game that cannot be overcome?
If the guard in the elevator room can be snuck past, then I'd love to see a youtube video of someone actually doing it.
I think you were being very diplomatic when you called the stealth system of this game "inelegant". IMO a more accurate description is broken.