Wasn't there a novel that explained the existence of Miri's Planet as being an actual quantum duplicate of Earth created by a spatial phenonenon at some point in the past and that her "Earth" was for all intents and purposes an alternate Earth deposited in a distant sector of space and one that evolved along its own social and technological paths by that Earth's 1960s?
If so we could think of Miri's Planet in much the same way as the Harry Kim created by the spatial scission in "Deadlock(VOY)," who was technically Harry Kim but also not. That would make Miri and the other Onlies human beings and not extraterrestrial humanoids and once Kirk's logs on the planet were received by Starfleet Command that could help explain why they dispatched specialists to aid Miri, Jahn and the others on developing their society along a new path now that they had the cure for the disease.
If so we could think of Miri's Planet in much the same way as the Harry Kim created by the spatial scission in "Deadlock(VOY)," who was technically Harry Kim but also not. That would make Miri and the other Onlies human beings and not extraterrestrial humanoids and once Kirk's logs on the planet were received by Starfleet Command that could help explain why they dispatched specialists to aid Miri, Jahn and the others on developing their society along a new path now that they had the cure for the disease.