Lalafell names continued... Siblings and lineage?

So we know how a Lalafell name is constructed, but how do the names relate to each other in a family?

I noticed the THM guild is staffed by a band of Dunesfolk brothers: Cocobygo, Cocoboha, Cocobuki, Cocobezi, and Cocobani. Additionally, there's another brother named Cocobusi. The brothers refer to each other by the second half of their name, so just "Bygo" or "Buki."

Is the "Coco" prefix determined by their family lineage, like a surname, or is it passed down from a parent in some way? Like perhaps their father has "Coco" in his name and the prefix indicates they're his sons?

And what happens when Lalafells marry? Do their names stay the same or do they combine in some way?

It could be that their parents liked the sound of the 'coco' names, and decided to give their sons matching names

Another question, I guess in regards to lineage. Does anyone know at what age is a Lalafell considered an adult?

There's a merchant at Highbridge who has a daughter in Little Ala Mhigo and the first couple of letters of their names are the same, if memory serves. I can't remember the names but they're part of the main quest line.

According to the Lalafell naming conventions, they don't have "family" names and their names are all individual. But I suppose the parents could use similar patterns for all their children.