That's all well and good, especially from a perspective of time rather than plausibility, but there's at least one thing working against those observations: it's been established that Reploids are robots (androids, sentient machines, pick a term), not cyborgs. The fundamental theme and backdrop of the Classic and X games are that these are technologically sentient beings, not biologically or evolutionarily sentient. You could split hairs and say something like Reploids and/or machines are made up of molecules or could use DNA as a storage medium for machine code instructions, but at this stage in the continuity, Reploids are nevertheless more machine than human ... and yet perfectly emulating those sophisticated, human cognitive functions like love, fear, and cogito ergo sum--"I think, therefore I am". That's what makes them interesting, even with a hypothetical use of DNA as a storage medium, but only up to such a point where the uniqueness of Reploids as a sentient specimen is preserved relative to that of a human specimen. If the writers and the fans just accept conflating traditionally biological terms and constructs like DNA and viruses, or poetical psycho-spiritual terms like souls, then they risk glossing over what makes Reploids interesting: how can they be so human-like? How do Reploids succeed or fail to emulate human behavior, or more importantly, human thinking and judgment?
I'm perfectly fine with a robot race and a human race reaching a sort of biotechnological singularity, but treating them like they work the exact same way en route and not trying to explore that further disappoints me.