Brian,
It sounds as if you have taken some excellent first steps in developing new sounds. Here is an idea for you to explore. Listen for sounds that have properties that you like. For example perhaps there is a guitar that has an interesting tremolo. Select it, go to Sound Edit and on to Tone and replace the guitar sounds with one or more of the electric piano sounds. Now you have an EP with the properties of the Guitar. This is just a quick way to discover a sound with new properties. it’s also easy to make some subtle changes using Easy Edit.
Frank