I find it a little odd that DARPA don't appear even slightly suspicious of the same things Rebecca is, namely that even if Taylor isn't a parahuman, there's something missing from the picture.
Especially since as I understand it she didn't actually figure out how the power supplied for gravity tech worked until some way into things.
Then again, once they find out she can reverse engineer tinkertech to a level that would make Dragon jealous, that becomes the simplest explanation. It's also quite possible they're aware she's working on tinkertech as a side hobby of sorts.
DARPA was approached by the professor Taylor went to. The one who read her, basically, "Screw your Understanding of Physics" work. The one
he understood. Then he talked to her at length about it, and she explained things with the absolute confidence of someone who wrote it.
And then he took that to someone else, and the same thing happened. Then she went to DARPA proper, explained it to their scientists (who understood, at least as far as anyone does when hit with a "All your Physics are wrong" discussion), and they and their engineers could not only follow along as she built a device based on her theories, they could replicate it without her. Which they did while subjecting her to all the "Are you certain you're not a parahuman" testing.
DARPA was suspicious as hell. But what they have is basically a new physics paradigm, one they can understand. No one understands TinkerTech, but they can understand this. They can derive things from this. They can
build things that only work if that understanding is true.
No black boxes, no magic, no shell games. "Here's how the universe works" and "Okay, if the universe works that way then Bob here can do X, Y and Z. Bob, go try X." and then X works.
That doesn't rule out some crazy thinker 10 "KNOW ALL THE PHYSICS" abilities, but that's not how thinkers work in general, and also they've subjected her to all the tests.
For her to do all this as a Parahuman who is just BSing reality, as opposed to "genius who just revolutionized science", requires her to be a high level Tinker and Thinker (to come up with an explicable and understandable basis for her new 'science'), a Stranger (to hide all signs of being parahuman), a Master (to be able to TEACH her BS physics), and Trump (to let anyone who sees her BS science and tries to build things off it make stuff that works).....
So either she's basically a genius who (admittedly with a little alien help to get her started), basically overturned the current physics paradigms and opened up a massively fruitful way to look at the universe OR she's the strongest parahuman to ever walk the planet, as she can literally force reality into a new shape, and give everyone who learns her views on reality the ability to make reality that way.