plisnithus8
Adventurer
On the first note, the "Wand of Orcus" isn't really a "wand." Even shrinking down to a mortal's size, it's more of a mace or a morningstar than a "wand." I'd say it is certainly over 5 or 10 lbs.
On the second note, in any event, I would definitely not rule that a Mage Hand counts as a "user" of anything. Even the Arcane Trickster's "Legerdemain" specifically calls out the use of thieves' tool [at a distance]-notably light, slender picks and such- and picking pockets as something that can do. Picking up a mace sized/weighted object, I think is clearly outside the feature's purview.
But, ya know, that's me and my rulings. Other DMs' rulings may vary.
Orcus is size huge (OotA p.245), but the wand changes to fit the hand of user. Both a standard mace and morning star are 4 lbs. each according to the PHB p. 149.
As for Mage Hand using it, I think that part it settled, but whether a player holding it gets any features without attuning seems still to be debated.