Substitutes:

• Brandy: Bourbon or whiskey can be used as a substitute if you don't have brandy. They both have a rich, warm flavor that works well in this cocktail.
• Lemon Juice: Lime juice can be used instead of lemon juice for a slightly different citrus kick.
• Simple Syrup: Honey or agave nectar can replace simple syrup if needed. They both add sweetness but also bring their unique flavors to the drink.
• Yellow chartreuse: If you are out of chartreuse, use another herbal liqueur such as Drambuie, or go for an orange liqueur for a more citrusy mixture.

Making a Pitcher of Brandy Daisy:

• To make a pitcher that serves 8, multiply all the ingredients by 8. That would be 16 oz of brandy, 4 oz of lemon juice, 4 oz of Yellow Chartreuse, and 2 oz of simple syrup.
• Combine all these ingredients in a large pitcher with ice and stir well.
• When ready to serve, pour the mixture into individual chilled coupe glasses, add to each one of them a splash of soda water, garnish with a lemon twist and cherry, and serve immediately.

Making it Non-Alcoholic:

• Brandy Substitute: Use a non-alcoholic brandy substitute; these are available and do an excellent job mimicking brandy's rich flavor.
• Yellow Chartreuse: Use a non-alcoholic option available on the marker or an honey-anise syrup. 
• Proceed As Usual: Use this non-alcoholic substitute instead of the regular brandy, follow the original steps, and enjoy a non-alcoholic version of this cocktail.

Making it Vegan:

• Simple Syrup: Ensure your syrup is made with white sugar or another vegan-friendly sweetener. Brown sugar, for example, is often not vegan as it can be processed with bone char.
• Yellow chartreuse: Yellow chartreuse includes honey, you can opt for green chartreuse or another herbal liqueur. Make sure to check the labels to ensure no animal-derived ingredients are used.
• Proceed As Usual: Once you've ensured all your ingredients are vegan-friendly, follow the original steps to make a delicious Brandy Daisy.