Is it *likely* for slow onset, bilateral, mildly symptomatic conjunctivitis to be chlamydia caused even with concurring genital infection undergoing treatment? (ocular symptoms presenting same day as genital?

Yes, it can. In adults, ocular chlamydia develops as a result of the introduction of the pathogen into the conjunctival sac from the genitals through hygiene items and hands contaminated with secretions.

Probably not. Bilateral and mild could be chlamydial conjunctivitis, but it's cold virus season, and conjunctivitis due to respiratory viruses is far more common than chlamydial. In any case, no worries: genital chlamydia treatment will be just as effective for conjunctivitis, if chlamydia is the cause.