Class 2A in Negima has many different creatures, such as a robot and a vampire. In fact, many of the students in class seem to be non-human or at least weird. Was there a reason given for them all being in the same class? Were they all purposely put in the same class or was it a coincidence?
Most likely, it's purposely because the entire academy was run by mages, and they would know about most if not all of these cases. There also is the fact that a 10 year old genius mage was given that class specifically.
It will, though, remain in the realm of speculation as no such thing has been mentioned in the manga series.