I´m thinking about it for a long time.
Your theory is simply credible.
If we reach the dates, we can see that the first FF were made in the earliest ´50 (1953 to be more precise). Between 1953 and 1960 the Ff knew more variations, and in those variations there were lots of Lip Blancpains (some models with 3-6-9-12 dials and the same bezels than in the Milspec I). The MilspecsI were made in 1960 and some writings said that the Bulova proto were available for testing probably in 1958-1959. The TR-900 was made in 1964.
The most pausible theory is that, indeed, some similarities between the Bulova and the TR are due to the Military Specs (don´t forget that the TR resolved some "problems" of legitibility that appeared in the Bulova) and both were made to "answer the questions" for the US Navy.
1958-1959....1960.... and 1964....
Is evident that the earliest FF were made as a superb diving watch. The Mil Specs from the US Navy were simply (legibility, waterproof, rotating bezel, and so)... the earliest Ff gave it.
The moisture indicator didn´t appear in any Ff since 1960, with the Milspec, like in the Bulova (one year before, aprox).
So, IMo, the question is simply.... an icon watch (the FF) adopted the Military Specs from the US Navy (like the Bulova), added an moisture indicator (like the Bulova), the Bulova made an "identical" bezel like the one in some FF (don´t forget that the Rolex, for example, weared a totally different bezel), and the Blancpain FF resolved some problems that appeared in the Bulova´s protos (1960). Four years later, an Icon watch born... the TR-900.
Between the born of the Milspecs (1960) and the born of the TR-900 (1964) four years passed. It´s evident that the TR were made before 1964, tested by Us Navy, and saw the light some years later.
Probably, the Mother of all of them is a earliest FF... the Bulova, the Milspec and the TR are great and nice daughters of it.
The Milspec and the TR-900 are sisters... the Bulova is its "cousin".
Interesting, intriging and.... beautiful.
One more question, hermano.... in the net I´ve read that the FF equiped some armies.... and the Spanish army too... do you have some informations about it??.
Interesting and constructive post, hermano, muchas gracias!
Emilio