Place 1 vanilla wafer in the bottom of 24 foil-lined muffin cups.
Process bananas and lemon juice in a blender or food processor until smooth. Add ice cream; pulse 4 to 5 times or just until blended. Add 1 1/4 cups whipped topping and 1 cup wafer crumbs; pulse 2 to 3 times or just until blended.
Divide ice cream mixture evenly among muffin cups; cover with plastic wrap and freeze.
Top each ice cream cup evenly with remaining whipped topping; sprinkle with 1/2 cup wafer crumbs before serving. Serve immediately.