Yes, it will have shroud.
The relevant rule is:
303.4b The object or player an Aura is attached to is called enchanted. The Aura is attached to, or “enchants,” that object or player.
There is no mention of controllers. Something with an Aura attached to it is enchanted, regardless of controllers.
And yes, it does work for a land turned into a creature. The technical details (rules section 613 – Interaction of Continuous Effects) are that type-changing effects are applied in layer 4, while ability-adding effects are applied in layer 6, thus the effect making the land into a creature is always applied before Greater Auramancy's effect.