Indefinite pronouns and obscuring the agent

I've tentatively created a new particle, ki, equivalent to "oni" in Esperanto or "me" in Yiddish. The idea is that it stands in for a participant without revealing its identity, either because this is unknown or irrelevant, or because its referent is general.

For example, a sign in an occult shop window might say Ki luke po lisu ne tia "Omens read here." The English translation raises the question, though, of how this putative form differs from a straight passive clause like Po lisu i pa luke ne tia.

I feel like there's a definite pragmatic distinction. Let's look at a different situation: suppose it's our Christmas party and everyone is drinking mulled wine. After playing the guitar for a bit, I go back to my glass and discover with surprise that it's empty, as it had been nearly full when I left it. When Amelia asks what's wrong, I can answer in a number of ways:

1. Ka sahi ni i si pa ipo!

2. Ki si ipo ka sahi ni!

3. Huka i si ipo ka sahi ni!

4. Keka sa si ipo ka sahi ni?

1. Straight passive. The arguments are right, but the focus is wrong: here we're focused on the wine, and the current state in which it finds itself (i.e., drunk).

2. Indefinite pronoun:. I feel like this gets at what I'm trying to say better. I'm focusing on the drinking, and the agency/volition whereby it was accomplished, while allowing the actual agent to remain unnamed (in this case, because I genuinely don't know who it is) and unemphasized.

3. Existential complex. Both this and the previous sentence could be glossed by "someone drank my wine!" in English, but there's a very important semantic/pragmatic difference. Huka can mean "someone" -- literally "some of those currently on the discourse stage" -- so it could mean "some person," but is more likely to have the force of "one of them." As such, it's far too accusatory for the intended meaning, and focuses too much on the agent herself rather than on the action.

4. Identity question. I put this in just for fun as an example of how we could get at a very similar meaning in a totally different way. This suffers from the same problems as 3 above, but with the right intonation and humorous atmosphere could still be an appropriate response.

Based on the above, it seems to me that ki is justified, but we'll leave the matter open for now. I'm making a lot of assumptions in my analysis that are based on English focus, and I'd better be sure that this is what's happening in Koa as well: otherwise, if the straight passive is more neutral than in English, for example, there would really be no need for ki.

"Do they speak Koa in New York?"

Ai ki puhu le Koa ne le Niu Ioliku?

Ai le Koa i pa puhu ne le Niu Ioliku?

And so on.