"...COVID-19 has parts from covid, SARs and HIV... so a PCR test would mostly test positive for any and all three tests."
Not any well designed test. It doesn't have to select only from those parts in the various progenitor virii, but can home in on unique features of SARS2, which is what any competent manufacturer of PCR tests would do.
"If people can get reinfected with COVID-19 as many have reported (so no antibodies.. or something completely different) then we are going to see the 2nd wave be really bad."
What seems to be going on is that any immunity only is developed in the young, and older folks aren't getting immunity. There's also been research that reveals SARS2 is able to infect nerve cells, and enter a state of dormancy, like herpes virii, from which, like herpes virii, it can re-emerge later.
In second waves of infection, folks that did not develop immunity from the first infection are nonetheless sensitized to the effects of the pathogen and all SARS vaccine trials (SARS-CoV-2 is a SARS virus) reveal increased morbidity and mortality upon infection after vaccination, so more harmful disease and more deaths the second time around. Estimates I've seen indicate up to 20% mortality from the second wave of infection for previously infected people.
The infection of nervous tissue also may explain why one of the symptoms of covid-19 is the sudden loss of the sense of smell, and why we see folks just suddenly keel over dead, as infection and destruction of autonomous nervous system mechanisms that control heartbeat and breathing would cause.
The chimeric nature of this pathogen is startlingly different from other coronavirii, and the research into what it actually is and causes, how it will behave, and much else is just beginning. Let's hope recent publications and papers seeking to downplay the severity of the initial flu-like symptoms is borne out as more data is gathered and considered.
Let's also hope persistent symptoms unlike anything other respiratory virii cause are shown to either have been misunderstandings or faulty data. The present suite of effects claimed includes AIDS, sudden death, infertility, no immunity and actual sensitization to re-infection, durable persistence in nerves and unpredictable re-emergence, and loss of sense of smell. I'd really rather deal with the flu.