[Genome] Humble Beginnings

Chemical senses, 'smell' and 'taste' although in a liquid element they are pretty much the same damn thing and primitive photoreception (which we could call a primitive 'vision' if we don't mind doing a gorss aproximation, although it'll really be of the level of 'bright over there, less bright over here)). it's pretty much the first senses ever and those that make the most 'sense' for a simple organism.

> Proprioception
"the sense of the relative position of neighboring parts of the body and strength of effort being employed in movement."

Proprioception only really amke sense if the body is develloped enough to have 'parts' , or at least limbs. Which nfrom the OP seems not tbe the case, I think we're talking 'unicellular blob' level of complexity here.
(I guess flagelae and tendrils are a thing but still not exactly rpoprioception per se...)