Is a slight overbite the "normal" positioning for the upper and lower jaws in people?

Correct: The slight overbite results in posterior disocclusion when you slide your jaw forward. This is perfectly normal.

Yes, is normal: Overbite means how much your upper and lower front teeth overlap when your teeth are closed. Depending on how the rest of your bite is set up, normal overbite can range anywhere from 10%-75%.

Yes it is: The normal overlapping of the upper front teeth over the lower front teeth vertically called overbite , and horizontally called over jet varies from 1-3 mm for over jet and same for overbite not to exceeds the upper third of the lower front teeth.. Hope that help..;).