All 3 will fit your criteria. Hogs can ocassionally be touchier as far as temperament, but there are many that are quite docile. Male dumerils usually Max out at 7-ish feet, although the females can get larger.

Personally, I would recommend a Dum as a first boa. They are highly underrated. And even though they are at the upper end of your size limit, they are extremely easy to handle and often very sweet.