If you only need ajax sniffing, can't you just shim the global ajax methods directly, regardless of react? Eg. replace window.XMLHttpRequest with your own object and window.fetch with your own function.
I might end up having to do that, it's kind of the nuclear option. I really just want only one bit of data, and I know exactly where the function that gets it is in the webpack, via the Chrome debugger which lays it all out-- I just don't know how to get to it from window.