Considering the problems with it I think you paid a little too much for this, If I were paying that amount of money I would be expecting the bike to be in good condition with all the equipment functioning properly!
Right, having said that!
Its difficult to comment on the head lights, I expect the lights now fitted arent proper vehicle lights and will not give the right beam pattern, I think you should put back the original headlight ASAP, Mirrors are a benefit to the rider, I dont think they have to be fitted by law, but riding without any at all is madness and dangerous, so I reckon you should buy these also and a speedo cable, just get it all back to standard, i dont think your GPS speedo will be acceptable if a policeman pulls you over!!