In my Son's experience the HA D1 RC/HC that were really serious not only did an academic pre-read, they also asked for financial information to see what kind of FA he may qualify for. This way a player can make an informed decision academically and financially. Summer before or Fall of Junior year of high school is typically when the D1 HA will do their homework and offers. Son's experience for the application process was that some requested ED and others requested general admission application.
With the D3 HA our experience was most could not offer any guarantee for admissions. However the couple that my Son was interested in and that had great interest in him, requested a pre read and followed up with and offer. It is my understanding that some D3 HA have 3-4 slots they can get academic support and hopefully a player can get one of them. My Son was offered one and was given a short time frame to accept and apply ED.