First, the chance of catching herpes from a single oral sex exposure is extremely low. The combination of that low risk plus the negative blood test 13 weeks later amounts to 100% certainty you didn't catch HSV from the first exposure.
Second, both the symptoms and the negative exams by knowledgeable doctors -- a dermatologist in particular -- argue strongly against herpes from the second pair of exposure (condom break and another oral event).
To your specific questions:
1) I recommend against further testing. The chance of herpes is too low, and although the available blood tests are good, they aren't perfect. The chance of a misleading false positive result probably is higher than the chance you caught HSV from the April exposures, so why bother? But if you insist, just have the test at 12 weeks. It's time since exposure that matters, not symptoms.
2) Although true that the blood test misses a few infections (around 10% of HSV-1, probably 1-2% for HSV-2), the combination of low risk exposure, lack of typical symptoms, plus negative test results is 100% reliable for all practical purposes.
3) IgM indeed is a poor test. Don't do it; the results are more often misleading than helpful.
4,5,9) You are obsessing too much about these details. Initial herpes lesions often are widespread, recurrent ones in clusters. The symptoms of HSV-1 and 2 are not different at all, except in lower recurrence frequency for HSV-1.
6) Initial HSV symptoms occur at the sites where the virus enters the skin, typically at sites of maximum contact/friction during sex. Thus the head and shaft of the penis, vaginal opening and labia minor, etc.
7) No, this is not a valid assumption. On average, initial herpes is worse than recurrences, but still many new infections are mild or cause no symptoms at all.
8) I recommend no further testing.
All things considered, it seems apparent you are somewhat irrationally obsessed with genital herpes. Nobody wants it, but for the most part genital herpes is a relatively mild, easily managed conditions. It isn't worth the level of concern you seem to have. Take common sense precautions (condoms for genital sex with new partners, etc) -- then live a normal life without worry about it.
Regards-- HHH, MD