So, her menarche could have happened because she was, in fact, receiving hormonal treatments. Not because her body was itself producing the necessary hormones.
Absolutely. Signs of puberty were stimulated and observed in the BD boy that was apparently held on mechanical support for 20 some years, and he was far from starting when BD occurred. Jahi was on the cusp of starting, if she hadn't already started at the time of her death (judging by body characteristics, she likely had already started or was just mere weeks away).
Women have their menstrual cycles manipulated all the time by artificial chemicals, hormones, etc. It's not at all outside the realm of possibility that the chemicals required to begin such processes can do so when supplemented artificially.
Also, I think it's extremely important to remember that the suggestions or comments of menarche are all purely speculative, based on unsubstantiated claims by a mother who also claims her BD child is not actually deceased. She and/or her attorney claims this is in medical records, but this could also mean a thousand different things, including a mere note from a home-care nurse stating, "Cleaned blood off sheets which appeared to be excreted from you-know-where." It could even be as simple as, "Woke up from nap and mother stated she changed Jahi's pad and it had blood on it."
We really do not know what this evidence is they claim to have, and it's very telling that they would broadcast such an incredible thing for the whole world to know about ("my teenage daughter just started her period!" - who does that, really?!?!). It's even more telling that they would do this, without providing any evidence to support this claim - credible or not. No a single shred.
What we do have for evidence, however, is instagram posts from Jahi's cousin back in February where she made the claim that Jahi had started her period. This IG post lasted all of a day and was quickly deleted, but we did screenshot it for recordkeeping. And then we have Dolan/NW claiming with the writ of error coram nobis that Jahi started her period 2 or 3 months ago. What happened to February? Or did they just forget? Or more conveniently, it wouldn't have helped them very much to make such a claim the month after her death, as opposed to 9-10 months later. By convincing everyone several months went by before this happened, it lent the only credibility possible to their claim. A month after death, well, that was just strong evidence that she had already started or was within weeks of starting.