Hey, Lee - you are processing this really well IMHO. you phrased these as questions - but i think you already know the answers:
The whole process really made me question my definition of CSA.
Can I call it rape when he 'only' manipulated me into giving him oral sex at 5 or is it 'just' sexual abuse?
Did my father sexually abuse us even though he didn't touch us?
Could my brothers have had a sexual relationship on an equal level even though they where 6 years apart?
How far does this pattern of CSA go?
Am I just making a big deal about nothing?
YES - it is rape - and "only" does not even belong in this sentence!!!
it IS possible for abuse to occur through words, exposure to a hostile and inappropriately sexualized atmosphere and being subjected to voyeurism - what it sounds like you had.
any time the difference between the two parties is significant - in age, power, experience, and the younger or weaker is being coerced into sexual acts, it is most likely an abusive situation. i believe most definitions for minors cite more or less than 3 years as the standard.
God only knows with the others... BUT with you - it stops!
you are NOT making a big deal out of nothing. IT IS A BIG DEAL - and IT WAS NOT NOTHING!!! just look at the toll it has taken on your life to see that.