"a bunch of engineers in some US uni"
C and unix were written at Bell Labs, not "some US uni".
The basic guts of the pair were written by Kernigan and Ritchie (C) and Thompson and Ritchie (unix), not "a bunch of engineers".
The keyBr0ad used was the one attached to the computer that they had available to them at the time. Keep in mind that back then, having a "spare computer lying around to play with" was an anomaly, having multiple keyboards would have been a bloody miracle. It's actually a testament to the ability and foresight of the three that C and unix are still with us and in wide-spread use, and on nearly all hardware platforms, nearly half a century later. They may have their flaws (doesn't everything?), but nothing else in computing comes even close to them in their ubiquity.
Likewise, like it or not, American English is the lingua franca of computing (and by extension TehIntraWebTubes). That is the only real reason that many programming languages are US-keyboard centric. Don't shoot the messenger, I didn't make those decisions. Thankfully, remapping keyboards on a per-program basis is almost laughably easy with modern operating systems.