I am a postdoc at the lab of, say, Prof. Johnson. Together with a few students and external collaborators, we performed a research study and sent a manuscript for publication, where I am the leading and corresponding author. Prof. Johnson and I verbally agreed on the author's order and role before first submission. All other coauthors agreed as well (but this is not documented).
The manuscript has been accepted. After acceptance, Prof. Johnson asked me to e-mail the editor requesting changes to the author list. He wants me to remove one of the students (say, Jane) from the author's list because he (quote) "does not clearly see her contribution." I also know that Prof. Johnson and Jane recently got into a personal fight with each other. Apparently Jane borrowed money from Prof. Johnson and has not paid Prof. Johnson back. Jane has now left the lab.
I worked together with Jane, and I know she contributed with data analysis and creation of some figures. This is something I believe can be documented. I also believe that removing Jane could lead to an accusation of unacknowledged appropriation of her work. Additionally, if Jane's contribution is not enough for co-authorship, we would have to remove another co-author as well (which is not under discussion).
For this reason, I manifested my disagreement to Prof. Johnson, but he maintained his position. I asked if I could get written permission from Jane, but he said "this is not necessary." Finally, Prof. Johnson said that he would request manuscript withdraw or retraction, if I don't agree to remove Jane from the author's list. The institution where I work has a publicly known history of ethics violations, so I would not trust the internal committees to reach a fair decision.
What would you advise me to do? I would like to avoid a confrontation with Prof. Johnson, but I am afraid that such a request to the journal would cause the paper's acceptance to be rescinded. Also, recent ethics violations in our institution have been reported by international media.