Driftwoods are hardwoods, so they would work! Most of the petco driftwoods are mopani or malaysian driftwood.
Sorry, I have sandblasted manzanita and grapewood, not fresh off the plant or anything. The manzanita I used to use in my aquariums, and I'm pretty sure has no sealant, but no idea if the grapewood has sealant...