Good question, Megan! Usually, substitutions are made based on what role the original ingredient is playing in the recipe. Bay Leaves, for example, have many various properties- both magickal and medicinal.
For the Legal Blessings Spell, it looks like the Bay Leaf is being used for the following:
Bay leaves are used for good fortune and success. Wreaths of bay leaves were given to the victors at Pythian games, which were sacred to Apollo. Learn more about Magic with Bay Leaves here.
[From Spells8 Legal Blessings Spell]
For the successful energy you are seeking in the Legal Blessings Spell, you could substitute with the following:
- Basil- for good luck, success, and attracting money
- Peppermint - for purity, assisting with communication, prosperity, and fighting back evil
- Cinnamon - fending off negative energies, good fortune
And there’s always the very trusty substitute: universal Rosemary. Rosemary is a very diverse herb that can be substituted for nearly any other. It’s also inexpensive and can be found in dried form in most supermarkets.
For a more specific substitute or some guidance on how to go about choosing a substitue, you could explore the advice offered in the following threads:
There are also several witchy correspondence books that delve deep into spellwork substitutions- there’s lots to explore! 
Wishing you all the best with both your spellwork and the courtcase. May rightful justice be served! 
