Combine coconut, pecans, and margarine, press onto bottom of the 9-inch springform pan. Combine cream cheese, sugar, cocoa, water, and vanilla, mixing at medium speed on electric mixer until well blended. Blend in egg yolks, pour over crust. Bake at 350 degrees F., 30 minutes. Loosen cake from rim of the pan, cool before removing rim of pan. Beat egg whites and salt until foamy, gradually add marshmallow creme, beating until stiff peaks form. Sprinkle pecans over cheesecake to within 1/2-inch of the outer edge. Carefully spread marshmallow creme mixture over top of cheesecake to seal. Bake at 350 degrees F., 15 minutes. Cool.