Equal contribution for second and third authors We are six co-authors in an applied CS paper (AI). This paper has a "strong" first author who worked on this project for years. Two student authors (let's call them Alice and Bob) contributed to the paper, and the other co-authors are seniors.

Since Alice and Bob have roughly the same contribution, we use a lexicographic tiebreaker, and placed Alice before Bob. While Alice is (unsurprisingly) happy with this solution, it bothers Bob.

I thought of several solutions:


We stay with the lexicographic tiebreaker between Alice and Bob. 
Flip a coin to determine the order. 
Put an asterisk suggesting equal contribution to the second and third authors.
Other creative solutions?


My question is about option 3. I've yet to encounter an "equal contribution" remark that is not about the first author. Since there is a sole first author, is it reasonable to remark that the second and third have equal contribution? Any other thoughts?
To answer your question nr. 4 (&quot;Other creative solutions?&quot;):
Making explicit each contributor's role based on CRediT (Contributor Roles Taxonomy) may solve some issues.
Many publishers already support the integration of such formalized contributor statements.