look on the bright side for the time being, you may have saved yourself a motor by catching that loose cone in the water pump. once they come loose doomesday is on its way.
i assume you purchased a new water pump from ford? the whole assembly with the rear pump housing and a new plate pressed in place? other than that i can't really think of what else would cause the noise you described before.
the tensioner pulley shouldn't be real loose. just tight enough to keep a good amount of tension on the belt. if the squeaking that you hear is coming from that area, take a bar of soap, and VERY CAREFULLY hit the side/corner of the belt with it while the engine is running. believe it or not that worked for me in the past. i had a nice squeal coming off the belt on my cougar and it did the trick. its worth a shot anyway. just be careful doing it.
i remember you said you had your serpentine belt replaced. well what side is this noise coming from?? the front of the motor or the back of the motor? try the soap on the serpentine belt if its coming from there. you need to narrow down which side of the motor it's coming from though. it could also be the idler pulley (or any of the accessory pulleys) for that matter on the serpentine belt. the idler pulley is a known culprit, as is the alternator pulley, from what i've seen/heard.