Asymptomatic spreaders are common for virus. Most people (~95%) that get the polio virus has no symptoms or very mild symptoms. It makes very difficult to control outbreaks if you don't vaccine a the people that meet the known case, but also the people that meet them and perhaps another ring of contacts. (I think that smallpox have no asymptomatic cases. It depends on the virus.)
> Creepy Coincidence #2
The problems with conjunctivitis, headaches, gastrointestinal problems are common to a lot of virus. Fever is what you body do when there is a virus somewhere, and conjunctivitis is what your body do when there is a virus in the eyes. Most of these symptoms are generic. Also, the virus may have a mild symptoms most of the time and very strong unrelated symptoms in a few times. Take a look again at polio or for another unrelated case take a look at shingles.
The other problems in your list are direct consequences of the virus. In some case you can get a secondary bacterial infection in the lungs. But with HIV the problem is that it destroy the immune system and then you get plenty of secondary infections.
> Creepy Coincidence #3
Mass confusion and hysteria. I agree, but I don't think it is particularly relater to Covid-19. Perhaps you should compare it to the last pandemic, like polio before the vaccine.
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In general, I think it would be a good exercise to try to find the same types of connections between HIV and Covid-19 but using instead Polio and Covid-19, or HIV and Polio.