Penance's backstory ain't simple either, I grant you, but it's easy enough to grasp/summarise the deal with Penance compared to Monet's sisters. Maybe you age them up but to portray severe autism respectfully and explain why they're in a story after all this time, that's a big ask for two characters people aren't exactly champing at the bit for, even if I do take your point that they are PoCs.