I don't know how I missed it until now. Or how everyone else did. We should all be ashamed.
I was looking through the various items at the Prop Store's Pacific Rim Auction, and I came across Hannibal Chau's ring (which, of course, bears his symbol). Then I read the description for it, and did a double take.
Emphasis mine.
But can it really be true?
Sweet plasma casters, it is true! Slattern is the symbol of Hannibal Chau!
But how can this be? Slattern wasn't created until well after Hannibal Chau's operation was in full swing. This leaves us with two possibilities.
The first is that the prop store is wrong (it's a prop store, after all), and that Slattern's face is not unique. In other words, there was another kaiju at some point that had nearly the exact same face as Slattern. The problem with this is that out of all the Kaiju we saw in the movie, none of them had anything approaching similar faces.
So how could the Precursors have possibly come across Hannibal Chau's symbol?
That's right. They copied the design from Hannibal Chau, through the drift. It is the only way Hannibal Chau could create the design, only for the Precursors to use it later. It also explains why Raiju and Scunner went through the breach without Slattern and then waited: he wasn't finished yet.
I can only speculate about the Precursors' motives. Did they think Hannibal Chau and his symbol represent death because he profits from the deaths of Kaiju? Did they pick up on Newt's fear of being killed by Chau and hope they could evoke the same reaction in others with the same symbol? Did they want to drive a wedge between the PPDC and their source of funding by trying to imply that Chau and the Kaiju were in bed together?
I suppose there is also the third option of the ring simply being a sort of easter egg. But consider the following: del Toro has implied that the sequel we're all waiting for will feature a blending of Kaiju and Jaeger technology. The most likely way for this to occur (especially given that there will also supposedly be a Gipsy Danger 2.0, which implies humans will still be using Jaegers) is for the Precursors to start building Kaiju/Jaeger hybrids. To do this, however, it would have to be possible for the Precursors to understand the information they get through the drift.
What better way to hint at this than by having the Precursors copy a design they saw in the drift?
Beacham and del Toro might just be even more clever than we thought.