Zulie goes by female pronouns, and yes I agree with you Michelle. Zulie kinda shot herself in the foot by showing her likeness multiple times across her platforms if anonymity was the goal. Her whole article was about being able to go back to having a normal life if she decided to retire from writing, but we already know a lot about her, including what she looks like.
I do have one disagreement with you, however. There is at least one YouTuber who is successful under an alias and give interviews without showing his face. I know for a fact that the YouTuber CorpseHusband has given several interviews where the interviewers/editors blur out his face to let him keep his identity a secret. I think it can be done, but you just have to be much more careful. It might be more work than I think most people would like to deal with. At this point it comes down to how shy a person is and how comfortable they are with strangers randomly coming up to them if they become well known whether or not a pen name is right for an author.