Perhaps the best way to replace missing linkage is to refer to
the original drawings of the action.  A reprint of "Description of
Standard Pneumatic Player Action" by AMICA can be purchased from me.
I have all the surplus stock of AMICA  reprints.

Detailed views of all components are contained in this high quality,
28 page booklet.  $10 plus postage.

Bob Taylor
http://members.socket.net/~rtaylor/aeolian_pipe_organ.html