Hi Ulrich, welcome to the club! I don’t believe the mods you mention would have much effect on resale. Alembics are so unique, and each one a little different. They don’t seem to fall victim to the “everything must be original, even the frets” requirement that people impose on old Fenders and Gibsons. While Alembics admittedly take a substantial hit in resale from the original new price, used ones hold their value quite well. Generally you should be able to resell it for what you paid.
Bill, the guitar one