As far as Ps.cube goes I think it could displace natives but it would be really unlikely. for it to move from its niche into a forrest and live on native herbivore poo would be pretty rare but I'm not ruling it out.
as far as mushroom consciousness goes, I have no doubt mushroom have intelligence they have a complex relationships with heaps of organisms but I think human are pretty low on the list of importance. maybe I'm wrong. maybe they have been just killing time over the last 25 million years building connections with bacteria, yeasts , other fungi, insects, nematodes and herbivores etc. waiting for the one special human to come along so it can reveal themself to them.
we have such a human centric view of mushrooms we tend to anthropomorphise them.
my comment about mature fruit and open baskets is just the standard practice of mushroom cultures all around the world.