"It may have been possible to obscure the status of the original shareholders with the promise of "look no more financially interested shareholding" but still leaving the original shareholders to make profits?"
Seems unlikely, the 1945 charter amendment states: "The corporation has no capital stock."
But have a gander at it, perhaps there is more to it than I can see. The devil may be in the details :)
http://www.a2z.org/wtarchive/docs/1945_Charter_of_the_Watch_Tower_Bible_and_Tract_Society.pdf
I'll will say this to our collective dismay: People like law professor James Penton has also studied the document, and he made no bones about it.