1.An object is said to be in motion if it changes its position with time,with respect to its surroundings.(while an object is said to be at rest if it does not change its position with time with respect to its surroundings)
2.Yes,these 2 terms are relative to each other.
A passenger in a running train is at rest with respect to a fellow passenger who is tin the train with him,but he is in motion with respect to a tree outside the train.
3.Distance is mostly greater than displacement.Displace can be equal to distance sometimes but it can never be greater than distance
4.Displacement can be equal to Distance if object is moving in a stateline path
5.yes,displacement can be zero,positive and negetive as it is a vector quantity.
6.motion of an object is said to be uniform if it covers equal intervals of time
i'm getting late for my tuition,will answer the rest when i come back