I have been reading about Bill and Fleur's wedding in DH, and we hear about a lot of people with red hair who are presumably members of the Weasley family. We know that Arthur has two brothers (though we know Bilius is know to be dead), so how many members of the Weasley's extended family can there potenitally be? Cousins and the like?

We also know that Molly had two brothers, but they were both killed because of their involvement with the Order. But does she have any other siblings, do you think, or would they have been mentioned?

And how does this Aunt Muriel fit into the Weasley family?