There is fluidsynth~ . It should make possible to use soundfonts on the organelle patches.
If you only care about high quality sounds and a lot of variety of presets, I think this is the way to go. But keep in mind that the soundfont files are sample based, so you will not wave a synth patch like in the Juno patch where you can dig in and see how the sounds are made from scratch.
Don’t know for sure how and to what extend fluidsynth works on the organelle, because I still didn’t try it myself. I Just bought my organelle one month ago, still playing around with the weirder side of things. Maybe someone else can share his experience with this?