So can a new in box (NIB) Stern fit into a
Generation One [2000] Dodge Durango?

Why yes it can!

OK, that was too easy. How about two GamePlan SharpShooters?

What about two GamePlan SharpShooters and Pinlicious???

OK, maybe not. If we shoved the front seats forward, we might have been able to squeeze him in. Maybe. :)