Alongside the letter, it would help to provide documentation to prove that you are 100% responsible for your living expenses and cannot afford the LSAC fees. Including a rent letter, letter of any government assistance/benefits you're receiving, bank statements, etc. helps tremendously.

Interested in studying either virtual or in person! I'm based in NYC

I don't have migraines, but I recently submitted an accommodations request. It seems like you'll at least need a medical diagnosis and doctor's note. I recommend setting up time with your PCP or a specialist to get an official diagnosis and then also request them to fill out the qualified form. The actual tab to submit accommodations request is straightforward. The accommodations request tab includes a candidate form, where you'll outline the requested accommodations and statement of need. In the next tab you'll need to upload medical documents, the qualified form as filled out by a doctor.