Well turns out the juubi was just a nerfed Kayuga. Basically, Obito and Madara where showcasing her power, so she has feats. HQ stated that incomplete Juubi had chakra on a little planetary scale and this was confirmed by the Shinju's roots spreading across the globe. Sasuke and Naruto stated that Kaguya's true form is leagues above that state. And her weaker son did indeed made the moon as a dying man after removing juubi from his body.