As far as the fact that the GB owns the KH's:
http://jw-stuff.10001mb.com/Publications/Publications%20-%20Internal/CORP%20US%20June%202003%20NY%20Articles%20of%20Incorporation.pdf
Subject to the provisions of section 18 of the Religious Corporation Law, upon the winding up and dissolution of this Corporation, after paying or adequately providing for debts and obligations of the Corporation, the remaining assets shall be distributed to Watchtower Bible and Tract Society of New York, Inc. No assets will be deemed to be received by Watchtower Bible and Tract Society of New York, Inc., until such acceptance is evidenced in writing. If Watchtower Bible and Tract Society of New York, Inc., is not then in existence and exempt from federal income tax under Section 501(c)(3) of the Internal Revenue Code of 1986 (or the corresponding provision of any future United States tax code), then said assets shall be distributed to any organization designated by the ecclesiastical Governing Body of Jehovah’s Witnesses that is organized and operated for religious purposes and is a corporation exempt from federal income tax under Section 501(c)(3) of the Internal Revenue Code of 1986 (or the corresponding section of any future United States tax code).
There are similar Articles of Incorporation and Bylaws are for all corporations the WTBTS establishes worldwide. I have seen similar language in EU as well.
This is from the Bylaws:
Persons eligible for Corporation membership are only those who are fully dedicated to Almighty God, Jehovah, baptized as one of Jehovah’s Witnesses, are completely in harmony with the doctrines and organizational arrangements set forth by the ecclesiastical Governing Body of Jehovah’s Witnesses, and report ministerial activity to the [NAME] CONGREGATION OF JEHOVAH’S WITNESSES, [CITY], NEW YORK (herein “Congregation”). Anyone meeting these requirements who is at least 18 years of age shall be designated a member of the Corporation; persons not meeting these requirements shall not be, nor be deemed to be, members of this Corporation. Any member who moves from or becomes inactive in the above-named congregation or is no longer one of Jehovah’s Witnesses shall be automatically removed from membership in the Corporation without the need of his resignation.