If according to you nobody's seen Otto face to face prior to episode 6 then why would Kiyomi point out mistakes he's made? Shouldnt matter what he does if nobody knows who he is.
I just explained that his body movements are on KG records, now only Kiyomi, and probably Veronica, would notice the subtle discrepancies... which is exactly what Kiyomi says.
Not really. She was hacking blindly and got into the wrong system, happens to the best hackers. Nadia clearly found out something that Ronny doesn't want to get out, otherwise she wouldn't have been granted a meeting with Kane.
Cynthia did have her and Delilah trying to find out about "ST"/Island 4, more accurately Nadia stumbled onto Cole's prison, whether Cynthia suspected that Cole was at Island 4 or not is uncertain, and moot at this point.
Okay IF your guys' interpretation that Kiyomi is talking about Red Mask is correct then here are some facts that have to be true:
1) With the mask, hood, cloak, and Callista keeping her arms to her side, not only are her physical features hidden, but so are her movements. Therefore the only movement Kiyomi could have observed is Callista's walk.
2) Kiyomi was able to identify Red Mask by this walk along, therefore she has either previously met Red Mask/Callista or has studied her in detail.
3) Callista did not walk to the cove to meet Veronica, nor walk out of it, she rode on a boat, and committed minimal movements, barely moving her hands (she repeats this minimalist movement with only a single hand raise in her second Veronica meeting). Therefore, Kiyomi could not have observed her walk at this location, and thus had to have seen Callista walk at a different/earlier time.
4) Kiyomi is aware of what "it" is when Otto asks her "is it over before it even begins..."
This just gives even more evidence that Kiyomi is working with/for Callista, knowing who she is, knowing that she's hiding, knowing what her and DS's mission/plan/objective is, and assisting them in that endeavor (volunteers information about the siblings).
Regardless, this is a very unnatural way to communicate in the English language, and Kiyomi has no reason not to be direct as she wants Otto to understand her clear meaning. Likewise, Tess has no reason to be obscure here either, she baited fans to question who the masked servants are the moment she made masked servants, so it's not like we wouldn't already be trying to figure out who they are. Here is natural delivery would have went down:
K: "...but I'm a little disappointed in [Callista or your colleague/associate/teammate]" This directly identifies the wrongdoer, and not erroneously accuse Otto or the entire group when they are not at fault. As long as Kiyomi doesn't say Callista's name, and in a natural way, Callista's confirmation remains shrouded.
K: "No one else will likely notice it, but I did. She made a mistake." Again, Otto is not falsely incriminated in the mistake, the failure is correctly attributed to the culprit. Since Otto's party has 5 females and 2 males, saying "she" still allows Kiyomi/Tess to remain aloof to the player, while remaining exact to Otto (who clearly understands who Kiyomi is talking about). Both of the masked servants are clearly female, so all that this may confirm is that Kiyomi is talking about one of them, which Sharpshooter claims to have suspected from the beginning, so again, Kiyomi/Tess doesn't reveal anything extra.
K: "Yes. It's not enough to hide one's appearance." This and the following line about movements can stay, as it still doesn't narrow down from the 5 females. Yes, the two masked servants are the greatest culprits, but Kiyomi's words also apply to any imposter or spy-masquerading-as-a-slave. This is exactly the type of thing that happens in corporate espionage stories, which is what this game is, and what most of the characters are doing, both within and without KG.