Would a billet aluminium blades and boards work?
Yes.
No. More ductile, for sure, but not as stiff.
No. Aluminum is about 165 lb / cu ft. Carbon fiber/epoxy composite is only about 97 lbs / cu ft., but since it's almost 3 times as strong, the middle can be replaced by foam, which has a density of ~4 to 8 lbs / cu ft.
Aluminum foils are easy to make, but they're heavy and bend easily (not just flex, but bend plastically - permanently deform)
Of course, you could have figured this out on your own, but you're a lazy bastard.
