1. Do these symptoms sound like HSV? Would they continue this long?
No, it doesn’t sound like HSV to me
2. If so is it likely this is HSV2 given encounter was only oral and other individual had underwear on?
If it was only oral, the risk is HSV 1 which you already have and would be very unlikely to get this in a new location.
3. With test results negative and low likelihood of HSV2 orally is it safe to assume these symptoms aren’t HSV or could be HSV1 in genitals?
I believe it is safe to believe you don’t have HSV 2
4. I did take some zinc supplements following initial symptoms, would this impact test results at all?
5. I’m very healthy and eat clean. In general do healthy immune systems seroconvert faster? My rational here is that HIV patients seem to shed more and have more active symptoms which is a result of suppressed immune system.
I think it isn’t possible to know if seroconversion happens more quickly for people that are healthy or not. But people who have HSV 1 already will seroconvert a bit more slowly than someone who is HSV negative and acquires HSV 2. But your experience just doesn’t put you at any real risk of HSV 2.