Substitutes:

• Brandy: If you don't have brandy on hand, calvados is a good substitute that maintains the spirit of the drink.
• Sweet Vermouth: Dry vermouth can be used as a substitute for a less sweet cocktail. You could also use red wine for a different twist.
• Simple Syrup: If you're out of simple syrup, you can make your own by dissolving equal parts sugar and water over low heat. Alternatively, agave nectar or honey can be used for a different sweetness profile.
• Angostura Bitters: Orange bitters can be used as an alternative to Angostura bitters for a citrusy twist.

Making a Pitcher of Metropolitan:

• Scale: To make a pitcher serving 8, multiply all the ingredients by 8. That would be 16 oz of bourbon, 8 oz of sweet vermouth, 8 bar spoons of simple syrup, and 16 dashes of Angostura bitters.
• Mix: Combine all the ingredients in a large pitcher with ice cubes and stir well.
• Serve: Pour the mixture into individual chilled martini glasses, garnish with a cherry, and serve immediately.

Making it Non-Alcoholic:

• Brandy Substitute: Use a non-alcoholic substitute; several brands are available that mimic the flavor without the alcohol.
• Sweet vermouth  Substitute: try a non-alcoholic alternative or use an aromatized grape syrup.
• Angostura bitters Substitute: create your own herbal infusion using ingredients like gentian root, cloves, cinnamon, and other spices to mimic a similar bitter and aromatic flavor profile. 
• Proceed As Usual: Use these non-alcoholic substitutes instead of the regular ingredients, follow the original steps, and enjoy a non-alcoholic version.

Making it Vegan:

• Simple Syrup: Ensure your syrup is made with sugar, that is not processed using animal bone char. Alternatively, use agave nectar as a vegan-friendly sweetener.
• Cherry Garnish: Make sure to use fresh cherries or cherries preserved without artificial colors or flavors, as some may not be vegan-friendly.