Peter, thanks for the references. I checked some of the paragraphs in Takemusu Aiki, and I think I will return to my first view that there are no link between the word musubi and Osenseis use of musu. The reference to names of deities in the Kojiki doesn't support any link.
On the other hand I believe that the temptation to link musubi (connect) to musu in Takemusu comes from paragraphs like the one where Osensei writes that "..Bu must be connected/linked to the principle of the universe..." (sorry I don't remember the exact page somewhere in the pages 17-20 ;-)). Right after that passage Osensei writes "Takemusu no Bu, which gives birth to love(Ai wo umu "Takemusu" ..... ) , is different in quality from Bu that do not connect with the universe"
I am not surprised that non of the students did not have an answer to what Takemusu means, after all Takemusu origins somewhere in the cosmology (I don't know if that is the proper english word for it ;-)) of Osensei, as Steffan also points out.
Peter, do you know if anyone translated those pages from Takemusu Aiki?