Can you combine double eyelid surgery and traditional (bilateral) blepharoplasty in the same operation?

Creation of a crease is part of most double eyelid surgery as is removal of excess skin and fat. So the answer to your question is yes in general

Double eyelid surgery is a bit of an old-fashioned term, but refers to Asian blepharoplasty - which is upper eyelid surgery performed to address some anatomic features that are unique to Asian eyelids. During Asian blepharoplasty, excess skin and fat in the upper eyelid may be removed while also creating a stronger connection between the skin and levator aponeurosis or tarsal plate to create a supratarsal crease (double eyelid). To answer your questions more simply, yes unwanted skin can be removed while achieving a crisp double eyelid crease in the same Asian blepharoplasty procedure.

Yes it is possible to do both in the same surgery and may actually be better for you to save mulitple operations via the same incision. However, I would make sure that you're actually a good candidate for both because oftentimes what you see as "excess" skin with a monolid is "fixed" when you get double eyelid surgery.