I didn't really count the time after my m/c as a cycle... just because your body is still trying to get back to normal. I had 2 natural miscarriages though. After the first, AF didn't show for about 6 weeks. After the second... it took 11 weeks for AF to show. Following my first AF this time, I O'd earlier than normal (CD 10 instead of CD 13 or 14) and my cycle only lasted 22 days (normally 27). Today it is CD 11 and I really have no idea if and when I will O.
Yes you can ovulate before you get your first AF. I never really took any OPK's or anything to determine if and when I did. I am not sure about when 2 cycles is up... My doctor told me 3 cycles... but we just waited after the first AF to start trying.... but it took my body so long to get back to normal that I just couldn't wait any longer!!