Drill press can do everything you will be required to do, although not as quickly, but the others cannot. If you stipulate a jig and hand drill for boring the limb mounts, then the sander. Band saw is near useless for glass work. I have all three and only use the bandsaw to rough cut the riser, and it (glass) dulls the blade within 2". And I could as easily do with hand tools as it ain't precision work anyway. I use the sander for all the limb profiling, riser shaping, ect.
If I could only have 1 tool in the shop it would be the belt sander.