An easy way to create variety without a lot of work is to check some Free Stuff areas for character kits. Skin color and hair style will go a long way to differentiate characters. If you're trying to do this quick and cheap, I'd recommend playing with scaling to add variety to figure size. Scale down on the y-axis to make shorter but a bit thicker, scale some individual body parts (a little, not a lot). That way you don't have to worry about clothes morphs- all you have to do is use the same scaling settings on the clothes. (When you do this, conform the clothes first, and then apply the scaling settings. Conforming the clothes will undo your scaling settings.)