That's not really the Yakuza's style. They're basically a bunch of criminal ultranationalists. Of course if there's an economic angle they'll exploit it, but in general I think they have nothing but contempt for Al Qaeda and Arabs in general and I suspect Al Qaeda probably feels the same way about them. They'd probably provide Al Qaeda operatives with fake papers and guns for the right price, but I don't think they'd want anything to do with an actual terrorist operation. It would be bad for business.
Style or not, post 4 is an intelligence report.