In large bowl, combine shortening and molasses; blend well. Lightly spoon flour into measuring cup; level off. Add flour and remaining cookie ingredients to molasses mixture; mix well. Cover with plastic wrap; refrigerate at least 1 hour for easier handling.
Heat oven to 350°F. On well-floured surface, roll half of dough at a time to 1/4-inch thickness. Keep remaining dough refrigerated. Cut with 5x3-inch floured gingerbread man cookie cutter. Place 1 inch apart on ungreased cookie sheets.
Bake at 350°F. for 8 to 10 minutes or until set. Cool 1 minute; remove from cookie sheets. Cool completely.
In large bowl, combine powdered sugar, margarine, vanilla and enough milk for desired spreading or piping consistency; blend until smooth. Place 1/3 of frosting in small bowl; stir in yellow food color. Place 1/3 of frosting in separate small bowl; stir in blue food color. Leave remaining 1/3 of frosting white. Decorate cookies to resemble scarecrows. Using writing decorating tip, pipe yellow frosting to resemble hair and straw around neck, arms and feet. Use blue frosting to pipe on bib overalls. Make face, belt and buttons with white frosting.