Wow! I did not know of that node Martin! Sweet! I’ll add that to the toolbox!
Not sure it would work for what I need since the instances will be certainly animated and their position will change drastically. From what I understand this setup will change at every frame if something is animated in position?
Here’s the screenshot of my current node-tree. It works exactly as I need… but I would love to make it more future proof and add a switch. If enabled, every time I duplicate the object it would get the seeds (or the randomize pattern in the group input) to automatically change. If disabled, I’ld keep the manual approach with the seed (say if I want to use the same “instance” over and over instead of having variation).

It’d be nice to have.. but I got it where I needed it for now. Let me know if that makes any difference on your insight!