DC3 due in late May/early June. DS is Samuel, DD is Margaret. They are Sam and Maggie for every day use :)
Our surname starts with Br and rhymes with Stick. 
I would really like to use Dawson in the middle. It's a really old name in our family.
The short list is:
William
Oliver
Henry
Jack
I like William best, I think. I love Will with my other DC's names. However it doesn't flow well with Dawson, I don't think. I could use Frederick in the middle, after my grandfather, or Oliver is a possible middle with William. I don't like the possibility that he could be called Bill or Billy with our surname though.
I love Jack and like it with Dawson, but I think Jack is too abrupt with our surname. We are American so it isn't as popular here.
Oliver is DH's favorite. I like it but it seems too...something! However that's what I said for Margaret and it really suits her. I love Oliver Dawson Surname.
Henry is sort of tacked on. We like it but don't really love it.