Don Gusto,
Good catch. Necrons shouldn't get thier reactive hull save unless they are BFI'd. It needs a ruling though.
Roy,
The Spire deserves an article in Warprift. And a seperate pdf. Are you game?
Commx,
Orbital mines cost 5pts per launch bay, where a Kroozer has 4 bays, so +20pts. For random strengths, you'd have to pay for the maximum possible, this would only be for the Hammer. (Space Hulks are defences so they can't have mines!!!)
Note: Space Marines shouldn't be allowed Mines!
Cheers,
RayB HA