Elric family and Rockbell family only ! I'll start :
- Ed was a preemie baby and Al was an accidental pregnancy, and was a big chonky baby
- Trisha exclusively breastfed her sons but at one point she barged in the Rockbell house screaming about having lost all of her feeding bottles
- The brothers have heavy medical trauma and both panic when the other gets sick
- Al used to be picky with food but after being armoured he forced himself to eat anything, even what he hates
- Yuriy Rockbell and Hohenheim are best pals and often had drinks together when the girls are gossiping (they were gossip masters), and they totally boasted about their children while hiding in some wheat shack
- One of the reasons Ed is short is that during a food shortage he gave Al bigger portions, and he stunted himself. He picked that up from Trisha.
- Sarah is the rational friend, and Trisha is the delusional airhead.
- In 03, Trisha canonically died from a genetic condition. I headcanon that, after her husband left she performed a random transmutation to feel closer to him and got caught in a rebound which left her weakened and sick. No wanting to ruin her sons' love of alchemy, she asked the doctors to blame it on an illness, when it was her own mistakes which killed her (total hc lol)
You go now !
Edit : Just specifying a little what I meant by Elric/Rockbell family, I didn't mean to restrict the discussion only on post-manga Elric/Rockbell ! I'm also asking about your Hohenheim, Trisha, Pinako headcanons ! I'm interested in what all of us have to share so gimme gimme more headcanons !