Is he gay or not?

Hi there
As we know, subjunctive mood can be tricky for some non-native English speakers (including me) and I really need to know if my understanding here is correct.
1) If he is gay, he will join the parade. (He is very likely to be gay.)
2) If he was gay, he would join the parade. (He might be gay.)
3) If he were gay, he would join the parade. (He is not gay.)
Please correct me if you find my reasoning here not sound or grammatically problematic. Thank you in advance for your thoughts and suggestions. :-)

Number 3 in your example wouldn't apply at all, as you wouldn't use "were" with "he." (That's mixing a singular subject with a plural verb.)

The other examples would probably rely not only on context, but also inflection in order to convey the proper meaning. Without hearing the tone of voice or seeing the body language of the speaker, there's not much difference between If he is gay If he was gay.