As I understand it, your parents get the same surname as you, assuming you start off with a family, instead of as a ward of the state, and little else changes from that. You keep their genetics and so on, so...
If you do start as a ward, I assume you still get your chosen surname, and to my understanding, that remains the only way to start off without parents and with the expanded customization options wards allow.
Also, if you're starting as gentry or higher, I really don't see why you would want to start as a ward. You're not going to have a family to will you their land when they pass on, which, to me, seems to be the main appeal of buying a gentry package: being able to rent it out for a steady income.
(BTW, random question since we're speaking of this. Can we reset our surname reservation somehow? I got one for the Janoa, but I've since decided to be Dras and would prefer a Drasean one.)