I would put Money on the bet that Garp is leading "Sword". Coby is his right Hand in that Operation and Drake is one the Infiltration for Kaido. Will be interesting where "Sword" is Operation also, maybe it is mainly for Kaido right now, maybe all Yonko?
Beside that, about Sabo, if i may guessing:
I think the WG tried to kill Cobra and Vivi, to take over Alabasta. One reason would be Pluton, like already mentioned here, the other one is to include Alabasta to the Maingroup of MJ, so it is not the land of traitors anymore. So i guess they got cobra and killed him, but when trying to kill Vivi, she got safed bei Sabo, which got injured, but was able to flee (with the other commanders maybe). Now the WG is blaming Sabo for the kill of both for some ridicilous reason.
Thats the reason for the inside, for the marines. But the main-civilisation shouldnt know about this kill, they should just get the info they got attacked by pirates on their way home, because now, when they got killed in MJ, they got killed under the supervising of the WG, the Admirals, the Marine, the strongest force on "the good side".
That going around, will bring alot of Trouble, losing trust, creating chaos. When the WG and the Admirals arent able to Keep People safe in MJ, where all came together, how should they be able to Keep the People on other islands safe? This News can separate the People, the kings from the table and the Folks. It opens the way for People trying to trust stronger Forces, like Yonkos. If they can promise to be safe, it seems more and more trustworthy when These News spread around.