If you look at the Kodak kit with a bleach fix in it, you might see that the words "not for professional work" or something to that effect is seen on it. Even Kodak apparently made a low tier product. We knew that common bleach fix or blix formulas had defects and that is why we put so much work into the patented stuff!
All films used formalin to stabilize the dyes against fade and also to prevent the growth of mold and fungus. You see, Silver in B&W prevents mold and fungus growth, but in color film Silver is supposed to be eliminated. This is to give the best dye image quality regarding grain and color saturation. Retained silver increases grain and dulls the colors. In E6 products it also caused higher dmin.
In negative color processes, the bleach has 1/2 the burden and the fix has 1/2 the burden (so to speak), but in reversal films, the bleach has 100% burden and the fix has 100% burden (so to speack) as 100% of the silver is developed in an E6 film. This is a hard design challenge.
Now for the prebleach...Edetic acid? That is just EDTA. There must be something else in there. Now, frankly, IDK what Fuji uses but they were cross licensing things with EK in this regard. But there are 3 more possible answers. If something is below a given limit, it need not be listed in the MSDS. If it is proprietary, it need not be listed. If it is deemed harmless by some over arching government agency it is deemed harmless. And so, a secret ingredient could be Sodium Chloride at 500 mg/L. This is harmless, at a very low level and if patented is proprietary for this use and wins on all 3 counts.
Don't rely on an MSDS for a proprietary item!
And I have the patent for the use of Sodiium Formaldehyde Bisulfite in Stabilizers to prevent formalin odors. I am familiar with the need for it. You see, C41 films were updated to remove the need for Formalin, but E6 films were not updated.