Hi there
I can't answer all of your questions but my af returned when my DS was around 9-10 months old. I had no cramping or anything like that, it just appeared one day. It is possible to be pregnant before you get af back as you may have caught the first eggie, so maybe just do a hpt for reassurance. I don't think you can ovulate without af (unless you're pregnant of course!) but I could be wrong.
Hopefully someone with more knowledge will help you!
Take care
xxx