I’m really not exactly sure what qualifies, but the existence of an emergent system so has to be there. Does fungus communication give rise to a system that can build some kind of memory and refer to it to develop more complex behavior? If not, then it’s lacking the level of complexity to be considered consciousness. (But that’s just where I personally draw the line)
Eusociality has its own context. It’s possible for a hive to show complex organized behavior, but so would an infinite paperclip machine if it was to consist of a swarm of collector drones. A myriad of units with a set of pre-determined instructions can have complex organizations, which still wouldn’t qualify as consciousness.
Now, the brain scenario would definitely count since it consists of the necessary “hardware” to start generating its own abstract contextual model of its experiences.