Can you tell me if someone is heterozygous w/ the hemophilia gene, is it possible for them to still have factor viii deficiency?

Yes, in men: Hemophilia is a sex linked disorder and men develop the disease when there only x chromosome has the defective gene. See this site for more info. http://www.nlm.nih.gov/medlineplus/ency/article/000538.htm.

Yes: By definition, women are the only people who can be heterozygous for x-linked genes. 10% of women who are carriers for hemophilia can also be symptomatic because of a phenomenon known as x-chromosome inactivation. Factor levels in these people can be reduced low enough that they have symptoms (though not as bad a severely affected males).