(I can actually answer my own question to some degree: the "alphabetical authors" convention is also the norm in my own field of high energy physics. Only after I finally landed a tenure-track job and served on another search committee did I realize that folks from other fields of physics would see my lack of first-author publications as a black mark. But in principle, among those who know the convention, order ought to be unimportant, shouldn't it?)
Or use a pseudonym.
The digraph "aa" is an archaic representation of the modern character "å", the last letter of the Norwegian and Danish alphabets, and should be sorted accordingly.