Are there more Exceeds and dragon slayers other than the known 4? 100 Exceeds were sent to get the dragon slayers. Happy, Carla, Sting, and Rogue are all Exceeds who abandoned their missions. 

What about the other 96 Exceeds who are unnamed, unseen, and out of the picture? Does this mean there are 96+ more dragon slayers in earth land?
There is NO information regarding the said 100 Exceed eggs sent from Extalia, any answer would be speculative as best. 

Only information we have on them is that the Exceeds from Edolas are now looking for them. I doubt if we will get any information regarding them either. They were just meant to provide the plot device for the history of Happy and Charla.