Well, I have a Physics degree, but I'm not a true "radiation expert".
1) Cold fusion does not exist. But an experimental hot fusion reactor in Toronto is perfectly plausible.
2) Beta particles have a range of about 90 cm in air. So to detect it that way you would either need to be already looking at it, or there would have to be a deadly radiation leak.
3) It's my understanding that it is gamma radiation that triggers phosphorescence. Again, you would only expect this to be detectable if their was a deadly radiation leak, and one would expect emergency services to carry equipment capable of detecting it (in case of a "dirty bomb"). Along with any school or university science lab. I assume Toronto has those?
4) A fusion reactor would emit neutrinos. And I would expect any Starfleet Academy graduate to know this. These are basically harmless but difficult to detect. They would not trigger phosphorescence, but I would expect a Starfleet Academy graduate to be able to build a detector (probably van-sized) given time and 21st century materials. If they can't I'm flunking them on engineering.
5) Looking for "Noonien-Singh" in the phone book would have been considerably easier and faster. Kirk had already mentioned he had never heard the name, so that pointed directly to the change.