Q: Are all 'psionics' in this setting strictly related to warp phenomena?
I want to propose a mixed scenario, in which there is a mobile larval stage similar to wierd's plan, that during "mating" – between 3 units to start with, can evolve more and bigger configurations later if competition allows – the mating ritual forms physical bonds between units, cementing them together into a tube. Take the stronger, tougher dorsal layer of wierd's plan as the foundation for an outer shell while the delicate manipulators of the ventral section end up on the inside. This 'adult form' would have the combined neural capacity and memories of all participants, enabling it to be "smarter" than individual larvae. It thus has the capacity to use the now-internal manipulators for complex tasks no larva could perform alone.
Back to the psychic question: the adult's increase in capability comes at cost of mobility now that all the former legs are stuck in one mass. (I expect some creatures will evolve to leave the tips free for active defense, but then they are pointing every which way and the ones in contact with the ground/seafloor cannot shift the whole quickly.) It would be handy if these adults eventually find a means of communication with their more mobile youth. To ensure they get a steady food supply delivered, for instance.
If straight psionics are out something else could still substitute. Perhaps our electro-silicon tubes are covered in natural LEDs to flash messages. Or pheromones if you want to be boring.
Unset Symmetry (0):
Tubular Symmetry (1): Chaoskl21
Paired Symmetry (1): Taricus
Triune Symmetry (1): MetalSlimeHunt
Further Symmetry (Trigonal-60deg radial, truncated bilateral, "Weird's Symmetry") (7): Weird, Madman, Piratejoe, Glass, IncompetentFortressMaker, Kilojoule Proton, NG
Mixed Life Cycle – wierd's symmetry -> Tubular (1): mightymushroom
P.S. Also tried to recalibrate votes since so many came up while working. Apologies if I got yours wrong.