I just recently got an Organelle a week or two ago, but I really love it. Already played a gig with it! I've been working on ports of my generative pure data patches and if you use PD you will love it!
1 : I saw a post where they were maxing at around 80% CPU with something ridiculous like 800+ oscillators lol. Without the GUI, PD runs very efficiently, and the hardware / Linux overhead is really small since it is running Arch.
2 : I haven't and I think this will depend on how well you can write DSP in PD or whatever program you end up running.
3 : seems like 800+ oscillators. As a reference, superCollider has a maximum of only 256 oscillators even possible!
4 : I am running an entire generative sequenced groovebox / synth patch that I've been working on for a few years and am really excited to keep porting and creating with PD on the Organelle. Maxing out around 41% CPU right now.
5 : You can check out here. https://patchstorage.com/ The uploading has been messed up every time I've tried to upload, but hopefully they can fix it.
6 : I have been wanting to build basically this same thing for awhile, but ended up just buying the Organelle.. Linux + PD + hardware is a lot of fun.