Hi Stower,
I would not agree that the 3 symptoms you mention are consistent with bubonic plague, which hit mainly London in 65/66. Also, victims of the plague were given a hasty burial in a common pit for fear of contagion, without a funeral service as described in the song. It is interesting that at the time it was thought that cats were spreading the disease, and so an attempt was made to exterminate cats. This gave the real carriers, rats, a free hand to spread the disease further. The jury is still out on whether the Great Fire finally cleared the air, or if the epidemic had finally run it's course.