Ad 2) @splat21 sorry for the confusion: that is 2.93. Geometry Nodes develops really fast these days. This was just a fast demonstration of the principle, so I cheated and used a version ‘from the future’.
Of course, for the COLLAB we will stick to 2.92, but there are enough Nodes there to make something like this work.
And you do not need to delete the Group Input Node; I just left it unconnected (it was a Plane and I didn’t want to show it here…) The GN Tree needs to be connected to an Object. A bit like a Particle System, where you can decide to not show the Emitter.
In 2.92 you could just use an Icosphere and add the GN Modifier (Node Tree) to that!
in the Geo Node world, is this considered a “shader” node (e.g., it has green connections)?
absolutely not!
Those colors are independent from Shader Editor Colors.
Although Purple still means Vector and yellow color, but Grey means float(ing point number).Turquoise/green is used for Geometry and green for integers. Then there is white for a Collection, pink for a Boolean and blue for a String:

But these color may still change, as this is in early development.
If you want to learn more about GN look for Erindale on YT. He has some wonderful tutorials for beginners.
He also made this (only modeled a few leaves for the flowers, the rest is GN):
