If A is really set on taking a gap year, I would suggest making your college list with that in mind.
Each college will have their own Gap Year Policy. Some do not allow it, while others have stricter requirements for allowing it.
And to make it more confusing, Covid has impacted the use of gap year—you might find that colleges that did not allow gap year have eased up and now allow it.
So, you will need to research each college. This info is so new, and so fluctuating, there may not be current policy listed online. You may want to contact the college directly before A starts filling out an application.
Regarding Financial Aid, earlier is better for getting the best awards. It is doled out on a first come first served basis, and there are limits.