Random traits work the same as in Vanilla despite the different turns/years because named characters live the same number of turns. With 2 turns/year they live for a "natural" amount of years while in Vanilla they were almost immortal.

Sincerely some bit of randomization is needed but I also notice that there could be something strange with chances.

I have to trust though that CA code produces reliable percentages and chances otherway we could throw the game out the window.
80% of a 1% chance should give 0.8% and if you see the log on how ancillaries are acquired (you can see the random roll there) I'd say it works.

I think here plays the theory that strange patterns are a lot easier to remember than normal patterns so they seems a lot far common than what they really are.

About the hereditary thing I fear it's something CA didn't code even if you can see foreign named characters in your family tree when you marry away one of your princesses to another faction leader or heir.

"+1 from popularity" is a CA thing, blame those aussies, mobilitate is mine though :P