Heat oven to 350°F. Lightly grease 8x8x2-inch pan.
Whisk water, 3 eggs, and 2 tsp sugar together using a whisk until the eggs are well blended. Whisk in the Meyer lemon filling mix until incorporated. Set aside.
Place cream cheese and 1/2 cup sugar in medium bowl. Using an electric mixer, mix on low speed until smooth. Add 1 egg and vanilla. Continue to mix on low speed until smooth. Set aside.
In a medium bowl, combine crust mix, melted butter, and graham cracker crumbs until a crumbly dough forms. Press dough evenly into bottom of pan. Bake 12-14 minutes.
Pour cream cheese mixture over hot crust. Whisk Meyer lemon filling mixture again, then pour Meyer lemon filling over cream cheese layer.
Bake 35-40 minutes. Cool completely at room temperature. Refrigerate and cut into squares. Best served chilled.