Well to answer different topics in one post
First as far as I am concerned Brain Alita and chip alita used to be one and the same person so as far as I am concerned they share the same childhood so unless we talk about a later part of the story there is no reason to differentiate the two.
Now about Yoko and royalty.
this one is tricky, well kingship is passed on by blood but not only, you can become King by way of conquest, or if you are acknowledged by the people for your deeds. Early Germanic Kingship worked that way: the role of the King was held by two people the rex who had a religious/ spiritual role and led the people in peace time. While the dux who was a war leader who was chosen on merit to lead the tribe to war. As time went by an individual would often assume both roles at the same time leading to the modern concept of kinship.
So If the reigning dynasty became extinct are chose to abdicate, Yoko could become Queen of Mars if the people chose her because of some deed she had performed.
But this is where it becomes tricky
Et le coureur à bout de force ... fut accuelli par une tempête de tollés!!!