You are not required to give your personal ranking of the school in your email. Your purpose in this is to give a friendly reminder that you are still actively hoping to get in to ALL of the schools that you would rather attend than the one you are in. You could have sent the LOCI weeks or months ago. What if your number one doesn’t ever go to the waitlist? Or numbers 1 and 2? Why would you wait to hear back until June or July that the waitlist is closed, before telling #2 again that you still want to go there too?
I like the ‘school x, I love your school because of y, and if admitted off your waitlist I would be thrilled to be a (insert mascot’), or ‘I will attend school x in the fall’. I absolutely would not put a qualifier of financial aid on it. You want them to pick you, not to have a reason not to pick you. If the financial aid doesn’t match your EFC it doesn’t, which is a reason to not commit, much like during ED.
You want your eggs in as many baskets as possible at this point!