I think I figured it out
@Amer, well the admin on the Chicken Genetics group on fb did. She says my Buff rooster is likely hetero for dominant white, and that is why the two chicks I hatched so far from the pair look so different. The one with the white patches inherited a copy of dom white, and the other chick didn’t. Makes perfect sense, since dom white is often used to clean up leaky black coloring in Buffs.
Here is a closeup of the other chick that didn’t inherit the dom white gene. Fascinating stuff..
View attachment 4260354
This one looks e+/eWh and Co/co+, Db/db+, could be hetero or homo for Mh, and Di/di+.
Definitely only split for Columbian because it has too much of the e+ down pattern to be homo for Columbian.