I think the Staffie has had most of it's bull baiting characteristics bred out now, but the big jaw muscles remain. If Jet were to turn it would be through nervousness rather than viciousness but that is less predictable. Put together with unpredictable toddlers would be a worrying mix. However, this would apply equally to many breeds. Jack Russells, I believe, have the worst reputation for biting - but with little jaws the damage tends to be less.
Jet has been a faithful friend to my mother and had a rather dull time of it. She deserves a bit of life in her old age.