We consider a simple information-theoretic model for evolutionary dynamics approaching the "coding threshold," where the capacity to symbolically represent nucleic acid sequences emerges in response to a change in environmental conditions. We study the conditions when a coupling between the dynamics of a "proto-cell" and its proto-symbolic representation becomes beneficial in terms of preserving the proto-cell's information in a noisy environment. In particular, we are interested in understanding the behavior at the "error threshold" level, which, in our case, turns out to be a whole "error interval." The useful coupling is accompanied by self-organization of internal processing, i.e., an increase in complexity within the evolving system. Second, we study whether and how different proto-cells can stigmergically share such information via a joint encoding, even if they have slightly different individual dynamics. Implications for the emergence of biological genetic code are discussed.