My apologies if this has been asked before, but you seem quite knowledgeable about the lore of Dragon Age, and I'm wondering if you can answer something for me: why does Lavellan have the surname of his/her clan? Does EVERYONE in clan Lavellan share the same surname? Or is it referred to in game as 'clan Lavellan' purely because of the Inquisitor's surname?
This has actually never been asked, but I’m super glad that you did!
So first of all, no it is not Clan Lavellan because of a gaming mechanic/reference thing. Also everyone in Clan Lavellan might have the same clan/surname, but they could have other names as well. Since other members of the clan remain nameless and faceless besides the Keeper, it is impossible to know for sure.
Dalish Clans are named for the Dalish Nobles who founded them after the fall of the Dales, in other words Elven Nobles from the Dales who started each clan. This means every clan is named after one family, even though it may house more. This also means Inquisitor Lavellan and their Keeper Deshanna (ridiculously long name) Lavellan are both descendants of the original leader/noble/Keeper of the clan, though it is never explained how they are related and could be very distant cousins. The reason this is known, because while they are of Clan Lavellan, they do not have to have/share the clan name as their surname.
Which brings us to the next point, there are some clans who were founded upon the names of two or more high-ranking elven families. The Dalish Noble then named the clan after them, while the other families within the clan kept their own surnames. The other families often being those of the legendary Emerald Knights, who stood as the protector of the Dales. This is seen in an example Mary Kirby gave, Clan Sabrae was founded by Dalish Noble Sabrae and Emerald Knight Mahariel. This means Clan Sabrae has the families of Sabrae, Mahariel, and other Emerald Knights existing within it. Hence why we get Tamlen Sabrae and (insert Warden name) Mahariel both in clan Sabrae.
Lastly clans trade members often, both out of necessity or excess of mages and to combat inbreeding. This is how we also get Merrill of Clan Alerion in Clan Sabrae.
So basically, no not everyone in Clan Lavellan shares the surname Lavellan. Clans are named after one, prominent family and other families exist and come into the clan as needed. Clan Sabrae being the perfect example, as it is made up of at least 3-4 known families/surnames. Inquisitor Lavellan is simply both from Clan Lavellan and has an ancestry linking them to the original Lavellan noble.