...expand itself exponentially taking over nearby space uploading all of humanity into a simulation
Ah yes, there's nothing wrong with murdering people as long as you name video game characters after them.
What's your justification for having P(she says "at least one is a boy" | 1B,1G) = P(she says "at least one is a girl" | 1B,1G)? Maybe the hypothetical mathematician is from a culture that considers it important to have at least one boy. (China was like that, IIRC)
Many in this world retain beliefs whose flaws a ten-year-old could point out
Very true. Case in point: the belief that "minimum description length" or "Solomonoff induction" can actually predict anything. Choose a language that can describe MWI more easily than Copenhagen, and they say you should believe MWI; choose a language that can describe Copenhagen more easily than MWI, and they say you should believe Copenhagen. I certainly could have told you that when I was ten...