Recoil
Regular
Its a really cool theory, and ties neat a neat sci-fi idea (DNA bonded links) into a major plot element. I'm sure if you mentioned it to JMS and he said its not that case, he will wish it had been.
My personal thought on this, is almost exactly what you had said. I'd bet good money that when the Triluminary was first created or introduced this was decidedly NOT the plan for it. But it is one of those B5 details that could easily have changed to fit the story as the story evolved because little information was given on it.
There were many elements to the show that changed from where they were originally intended to go during season one (or The Gathering), but JMS had made things work beautifully. Adding the line "Entilza Valen" as Kosh's greeting in "The Gathering" after the fact was a perfect example. Sinclair wasn't planned to be Valen then in the original run, but since the story evolved to that, it was added back in later. (And I think we all agree the story turned out 100x better than those early outlines). The Triluminary could easily be another detail like that, that seems to make more sense given how things ended up turning out.