GFI (controlled by Ghosn) paid SBA (an Omani businessman, Suhail Bahwan) for "marketing incentives." At some point later, SBA paid GFI. The Japanese suggest this was a kickback scheme but 1) the fact that one firm paid another and vice versa is not ipso facto evidence of financial wrongdoing 2) if this really is a kickback scheme, why such low sums of money relative to his net worth?
The other accusation in the articles you reference is that GFI made payments to a company named "Shogun Investments", of which Ghosn's son was involved, and that he directed those funds to his own financial startup, "Shogun Enterprises", which then possibly used the funds to buy a yacht.
The first charge has no clear basis for impropriety, and the second is against Ghosn's son, not Ghosn (and btw, even if Ghosn's son did misuse investor funds -- and he denies doing so -- it wouldn't be the first startup in the world to do so).
Unless you can explain to me something I'm missing these accusations do not strike me as "the elephant in the room."