As the forums increase, there are going to be a lot of similar usernames. Just look at all the "Raven" variations we've had, maybe a dozen or more? This could just be coincidence. "Shadow" is a common name for those drawn to the occult, and lots of people like cats and spell it as "kat", or could be someone named Katrina.
There have been 2 other Lydia's which were real people, not copycats. That's why I don't jump to conclusions.