Welcome to the forum.
First, it is unlikely your commercial partner had HIV. Your figure of 1 in 120 Toronto residents having HIV doesn't compute -- although I suppose it is possible if 5-10% of gay men in Toronto have HIV. As in most eastern North American cities, the large majority of HIV infections in eastern Canada are in gay men. Also, upscale (expensive) escorts are believed to generally have low rates of HIV; they typically get tested frequently and tend to have low risk clients (mostly heterosexual men like you). So the chance is very low your partner had HIV, probably under 1 in 1,000. When a woman has HIV, the average transmission risk is about 1 chance in 2,000 for each episode of unprotected vaginal sex. Together, those statistics suggest an HIV risk in the ballpark of 1 in 2 million.
Those comments address question 1. As for oral thrush, you are correct that visual examination can be very misleading, and thrush is not the same as white coated tongue, for example. In any case, thrush is actually not very common with new HIV infections; it is more commonly a problem in overt AIDS, i.e. people who have had HIV for several years.
Your comments about the reliability of HIV testing are about right. You should stay away from the oral fluids rapid test, which may take a bit longer than blood tests (either rapid or lab based) to become positive. A lab-based duo test would probably detect around 80% of HIV infections at 2 weeks. See the thread linked below for more detailed discussion, as well as the other thread linked in that one.
Bottom line: This was a low risk exposure with regard to HIV. Stay relaxed while you await the results of testing. However, I would encourage you to also be tested for gonorrhea and chlamydia, which are far more likely than HIV; and syphilis in a few weeks. I expect those tests, as well as the HIV tests, to be negative -- but better safe than sorry.
A final bit of advice, in a single word: Condoms!
Regards-- HHH, MD