If you didn’t get any applications in for EA Nov. 1 you really need to get some financial safeties added to the list and applications in right away. With the next student a Junior, would your eldest consider a gap year? With two students in college the EFC (per student) is greatly reduced.
I still think your eldest should apply this year, too. If there is a financial offer that works then you’ll be good, and if not trying again next year with two in school will help ensure the decision can be made knowing the financial aid offers for both since they are so close in age.
There are kids that end up with nothing working financially and having to re-apply with a gap year to be eligible for freshman renewable awards. Skipping applying as a senior makes pulling information together after a gap year even harder. Teachers should be able to reload recommendations etc. next year and won’t have to take time away from writing letters for next year’s seniors if a gap ends up being the only option.
UAH full tuition auto merit (housing added if scores go up to 1520+ or 34+) https://www.uah.edu/admissions/undergraduate/financial-aid/scholarships
Try the ACT, might be better at it and reach a 34 more easily than improving SAT to 1520.