If you're a director at AFI you can write your script for 1 out of 3 of the cycle films in the first year, and you can also write your thesis film in the 2nd year. Not sure about editing.
Yes this is true to a degree but you still have to work with a writer on your director led cycle film. Similarly, your thesis has to be chosen by the blind thesis committee and many directors do not get their scripts picked. For my year only about half of the directors had their thesis chosen. So, it’s certainly not a given. Sam Esmail’s thesis script was famously not chosen and allegedly to this day he refuses to give money to AFI because of it.
AFI is explicitly anti-auteur because the reality is auteurs are a dubious concept to begin with since no one really truly can make a film by themselves. Even if they write, direct, and edit they need others to pull it off. Several directors my year were disgruntled and viewed AFI as “filmmaking by committee.” To be honest that mentality is a red flag to other disciplines because everyone is specializing for a reason. Everyone is good at what they do and dismissing that makes the process like pulling teeth rather than everyone being open to input.
I can think of exactly 2 of the near 100 cycle films we made that were successful when taken over by directors who want to be auteurs. Most are critiqued quite harshly for it being apparent that the skills of the team members were not utilized effectively.
In regard to editing, you get to give input to your editor and the first cut is a collaboration between editor and director which is screened for feedback with the directors, then the producer is allowed in for the next cut and the rest of the team gives input before the fine cut.
For OP what you describe is how most film schools work. DePaul in Chicago for example does this as does Columbia College Chicago. I’d say required discipline based collaboration is more of an anomaly in film schools generally. I’d caution against believing that you can do it all even if you are reasonably competent at all 3 fields simply because if you want to make a career out of it you will need to collaborate with writers and editors at some point. Many directors find that they prefer working with editors in particular once they do it in my experience. People who are genuinely good at writing, directing and editing are few and far between and it’s usually a sign of having control issues which harms the final product more often than not. For every Ari Aster there are a thousand people who think they’re Ari Aster.
And just my two cents but programs structured that way tend not to guarantee you will make films in the way that AFI does. AFI pays for your cycles and a portion of thesis. They force teams to be built and while that may not work for everyone, in practice, it means that you actually make films because building a team around a film is challenging and I’ve seen other programs where people simply can’t get quality talent to sign on to be a part of their film team so they drop out, don’t make a film, or make a bad film. That said only you know what’s best for you. The only programs I know for sure require collaboration in the way you’re taking about are AFI and Chapman.