So just a warning, I'm new to the Create a pokemon project. I've read through everything though.
It's still the design of a suit of armor? How about have the spirit that's inside it either be a Banshee or a Poltergeist? Both ways, it could be more stall-oriented, with banshee giving it more of a "vocal" set of moves (Could explain perish song, etc), and Poltergeist could give it a chance for prankster ability.
Regarding moves otherwise, I'm thinking basic type attacks like bullet punch (maybe a technician ability?) and hex.
Honestly, design-wise, other than the basic "Suit of armor", just don't make it fly. Flying ghost types AND levitate is overused. I mean, they gave GOLURK fly. :I
Anyways, Names... Haubergeist? ((Hauberk as in suit of armor)) Or... I don't know. That's the only one I can think up.