* If someone has a negative test after treatment, but that’s not counted as “cured”, does that imply it could (or maybe will) come back if treatment is stopped?
Yes. HIV+ patients require antiretroviral treatment for the remainder of their lives. Most are able to manage with a pill regimen. This is not to say it is cheap or side effect free, but most HIV+ people are able to live normal lives with outpatient support.
(To link it back, PrEP is the same drug used to treat; ex, emtricitabine + tenofovir. Dosage, schedule differs. Other antiretrovirals may be chosen.)
* What’s the importance of the distinction between HIV+ vs AIDS, from a public health or human perspective? We don’t talk about influenza+ vs “has the flu”, at least as far as I know. Does HIV+ carry less stigma than AIDS?
Public health does talk about Inflenza (and other viral positive) individuals. Public messaging is usually with the term “carrier” - but in jargon, this implies that the individual will likely mot develop the disease themself, and will remain asymptomatic, which is untrue for HIV. NCoV-19, recently in the public eye more than any other virus, has a lot of literature around positive tests vs disease.