So are Distribution Nodes and their chance for infection / Golems and Resistence and where they appear \ stuck to the seed as well? Or is that truly random?
All of those things, plus any other capturables, are part of the seed. Again, those will vary by the above factors in addition to the seed, but that's all. The seed is meant to create an entire scenario, and the nodes and golems part of it.
Although: the chance for "realtime" events are completely random, and not part of the scenario. So, whether or not a distribution node turns out to be infected, when marauders or resistance fighters appear, where the AI attacks and how it reinforces (basically everything the AI does after the initial population of the map), etc.
In other words, the at game second zero, everything that exists on the map is affected by the seed. After game second zero, nothing more is.