There are plenty of JST footprints and 3D models in the footprint and 3Dmodel libraries, but I haven’t checked to see if the 3D models are complete.
You would use them with a generic connector symbol that has the same number of pins. I notice though that there is a MP pad on the footprint, probably for mechanical attachment and shleiding. You may have to add an extra pin to the symbol called MP to connect to that footprint pad.