I like1 and 3 a lot. 2 could work, though I’d be interested to know what factors are driving this cultural shift among dwarves.
I'd say it is a shift from the dwarf clans being from"just families" to "clans as occupations.".
Basically a class system. Once dwarves become stable enough to specialize, class roles, job roles, age roles,and of course gender roles become a thing.