Yes he did own slaves. Everyone that was wealthy at that time had slaves. Since he worked in congress and as a lawyer he was bound to make good money
Yes, he owned seventy Slaves and he was a decent slave owner, not letting anyone whip them or split apart their families. :)
No Adams never bought a slave and declined on principle to employ slave labor. Abigail Adams opposed slavery and employed free blacks in preference to her father's two domestic slaves.
I believe it was 17
No, he actually was one of those who condemned slavery.