[Note the title of the thread: this is speculation only, and for the purpose described below]
In investigating whether there was any collaboration or ghost writing involved in "A Few Days In Athens," I have no desire to take any credit from Frances Wright, but I simply cannot see how the same person who had the insight to write "A Few Days In Athens" could not write anything else at all about Epicurus for the rest of her life, as it appears was the case for Frances Wright. I have long thought that the "aside" within AFDIA where she criticizes the philosopher whose work was virtually Epicurean but who distanced himself and gave no credit to Epicurus was a major tip as to the origin of the book. That sounds pretty close to self-criticism to me, and it would not apply to Frances Wright herself.
Even if she wrote every word of it herself, it is likely she was influenced by others beyond Bentham (to whom she dedicated the book and could conceivably have been a participant in it too). But if she was largely raised by James Milne (John Stuart Mill's father) then it would be apt to investigate that influence too, always with the goal not of removing credit from Frances Wright, but to build our understanding and possibly locate other writers whose material could be of help to us in studying and understanding Epicurus.