Combine wafer crumbs, chopped nuts, butter and 1/4 cup sugar; press onto bottom of 13x9-inch pan sprayed with cooking spray.
Beat cream cheese, rum extract and remaining sugar in large bowl with mixer until blended.
Add eggs, one at a time, mixing on low speed after each just until blended. Stir in mashed bananas; pour over crust.
Bake 30 min. or until center is almost set. Cool. Refrigerate 3 hours.
Slice remaining bananas; toss with lemon juice. Spoon over cheesecake. Microwave caramels and milk in microwaveable bowl on HIGH 2 min.; stir until caramels are completely melted and sauce is well blended.