Yes. Depending on the severity of the disorder will dictate if it is safe to proceed. How your coagulation profile responds to administration of dictates the effectiveness of treatment and safety of surgery. The costs of preventative treatment is very highland has risks as well, asking the decision to proceed with elective, cosmetic surgery more complex!
Probably. I would get you cleared by your hematologist first to limit the risk and get guidance. Bleeding issues should be minimized beforehand.
Hemophilia & tummy. In my opinion, i would only consider this after a full consultation with your hematologist. It may not be worth the risk. Von willebrand's disease can vary in it's severity. Elective surgery can be planned and medications provided to minimize the potential for bleeding. However, surgery should be planned with the possibility that bleeding may occur and require additional treatment.
Sometimes. If prepped and cleared by hematologist.