I think weight is defined by the interaction between an object and the planet that you're using as the reference point for the object. So a weightless object would also effectively have a mass of zero. Of course, there's no real reason that D&D logic has to quite work like that. Or maybe the object is just almost weightless. Whatever, it doesn't really make sense.

Like, for nonmagical flight, a weightless object is lighter than air, so it sails upwards like a helium balloon. A bird's wings are also weightless, so it can't use them to exert normal force on the air beneath them to fly.

I missed the feather fall effect. If that's meant to save items you should specify the duration of that effect as well. Now that I'm looking at it, that's probably not enough since it would only affect the object for a few rounds. That would barely alter the descent of an "orbital" drop.