I’d rather be a bit more pessimistic than optimistic in this regard. I think that applying ED does give the applicant a better chance of getting full need met. It makes no sense to accept a student early, knowing you are not meeting need, even at a school that does not guarantee to meet full need. I also believe you have a better chance of discussing your award directly and seriously with the financial aid director if it is not doable, and comes down to having to withdraw from ED if more money cannot be made available. The FA directors have more time to address this issue early, and the school has a strong incentive to keep all of their ED accepted students.
But merit money doesn’t come from the financial aid office at many schools. It comes from admissions. It often isn’t even offered ED. It is usually a sweetener offered up at the end of the app season to try to get the most desired students. ED kids are a done deal. No reason to throw money at them. There are merit awards that blindly consider all students regardless of when they applied, but a lot of merit money is used pragmatically. I do not recommend ED for those who need or really want merit money. I do recommend it for those who need financial aid as long as they have done their homework with NPCs and know what they can expect to get in terms of aid from a number of colleges, including peer schools to the ED school.
Ideally, OP would pair AU app with a few EA or rolling ones that are even less selective and where merit money might be in the picture. Maybe a peer school too. I’d throw in Tulane, St Joe’s, Lasalle, UMD, Pitt. Some other EA, And rolling schools, especially if there is financial need.
I think OP will get into AU but get zero merit money. If financial need is in the picture, I think AU will meet full need as they define it even though they do not guarantee to meet full need, nor do they meet it for everyone. They also state that ED applicants are treated the same in regard to getting Fin aid as RD applicants. AU claimed to be need blind in admissions last I heard.
I do not know what OP needs in terms of money for college, whether Fin aid is in the picture at all