Responses
I think it's considered a reverse harem because FL don't choose a ML. And I didn't read the novel so I can't be sure but I guess we will not see any romantic scenes with any potential ML's, just friendly vibes/friendzone.
Because story build around Hailey taking revenge (potential ML's with us mostly as supporting characters)

It has a very good plot until I heard it is a harem one. You could build the story many ways but ending it with harem will not be satisfying for me. She could choose one or not anyone but choosing everyone is i think clashing with her morals. Like I know she is weak to handsome faces but polygamy is totally othe thing.. dropping