ng - you have got something very wrong with your pano head. there are no straight lines at all in that scene. if you are just practicing i understand but if that is something you are going to showcase you work with you might want to recalibrate your head or try to fix it with the stitching software. which sticher do you use? ptgui can add horizontal and verticle sets that will force things straight it might be able to fix that.
dont have a ipad so i cant say what to do with the missing cube face.