In their debut in "Beyond the Forest", the ConHares all looked similar. The first ConHare, (nicknamed "Cesario" by J&D) was the tallest, the second one (nicknamed "Brian") was fat, and the third (nicknamed "Jeffery") was the smallest and also youngest.
In their later appearances, two of the ConHares were redesigned. Brian now has a slightly visible buck tooth, and no hair. Jeffery has lighter fur, a bi-colored shirt, hair tuft, and some shoes. Cesario, on the other hand, remained the same as his debut appearance.
In "Beyond the Forest", the ConHares all behaved the same; cunning, tricky, and villainous. They were willing to capture PJ Raccoon, and take him to their master.
However, in later appearances, they somehow got different personalities. Cesario retained his cunning personality, but he is now also a suave, charismatic demeanor which usually helped him pull off his scams. Brian became greedy and dimwitted, and was shown to have made a few mistakes in his life.
Jeffery, being the youngest of the ConHares, didn't want to be evil, and always thought of becoming a good guy. He also gets frequently picked on by Brian.