Yes.
Depends on how you do it?
Seen it done well once, and poorly once.
Leaf springs are a simple suspension. Therefore, you can "design" one fairly simple.
The hard part is making sure where you mount them is strong enough to handle it on the unibody.
I may be wrong but it just seems to me like coils and 4 link would be the better way to go. After all, it's already all there. You can get a budget kit for like 300 bucks.