Using electric mixer, beat cream cheese, 2/3 cup confectioners sugar, lemon zest and vanilla until light and fluffy. In separate bowl, beat 3/4 cup cream until stiff peaks form; fold into cream cheese mixture.
Line 9x5 -inch loaf pan with enough plastic wrap to leave overhang.
Arrange single layer of cookies (about 10) in bottom of prepared pan, overlapping slightly if needed. Spread one-third of cream cheese mixture over top. Top with 1/3 cup mango and 2 tbsp almonds (if desired). Repeat layers twice, ending with layer of lemon snaps on top. Cover with plastic wrap overhang; freeze for 2 to 4 hours or until thoroughly chilled and set.
Before serving, whip remaining cream and icing sugar until stiff peaks form. Invert cake onto serving platter; remove plastic wrap. Spread top and sides with whipped cream. Garnish with remaining mango and almonds.