Combine white vinegar, stick cinnamon, sugar, allspice, and whole cloves in a medium saucepan; bring to boiling. Reduce heat and simmer, covered, for 5 minutes. Remove from heat and cool. Place green grapes (about 1-1/2 pounds) in a large bowl; pour vinegar mixture over grapes. Cover and refrigerate for 4 to 24 hours.
Stir together cream cheese; pomegranate juice, pomegranate molasses, or grenadine; lemon peel; and mace in a small bowl until smooth. Cover and refrigerate for 30 minutes or up to 1 day.
Using a pastry bag fitted with a large decorative tip or plastic bag with corner snipped off, pipe about 1 teaspoon of the cream cheese mixture into dates; pipe about 2 teaspoons cream cheese mixture into the lower third of each endive leaf, then sprinkle with almonds.
To serve, remove grapes from bowl with slotted spoon and arrange in a mound on a serving platter. Arrange stuffed dates and endive leaves around grapes. Garnish with lemon slices and pomegranate seeds, if desired. Makes 12 servings.