It makes the most sense!
Think about it: Admirals Fujitora & Ryukugyu were busy with the Revolutionaries and wouldn't be given such order anyways, since it's something Secret Services (CP0) would take care about. Sure not a Navy force but a Governament one.
This excludes Fleet Admiral Akainu and Admiral Kizaru too...
When it comes to Governative agents, specially CP0 who carry the most important mission (like the elimination of a King), the agents who were in security duty at Mary Joise during Reverie were:
- Rob Lucci
- Kaku
- Stussy
- Tribal Mask
I would exclude Kaku and Stussy for obvious reasons, while Tribal Mask doesn't seem to be an extraordinary agent on which the Gorosei would entrust such delicate mission.
This leaves Lucci, a talented assassin with taste for blood, who also happened to be the security leader during the event (or at least looks like it). Sounds like the perfect guy for the job.
And is the same Lucci who was glady accepting the order to kill one of the 20
Kings of the lower realm (Neptune):
Also, with Vivi herself (Imu's last choice) facing Lucci to stop him...
Looking at Imu's decision, Vivi was probably the real target entrusted to Lucci but something went wrong and Cobra got in the way to save her. I suspect Sabo was there for two reasons:
- He was the one warning Cobra of the danger he was in and the one who saved Vivi before taking her with him, which explains why she is MIA right now
- He was the scapegoat used by CP0 (and Lucci in first person) to unload the crime on when they failed to keep it secret and the info became public
All this rafforces the Sabo // Lucci conflict which is slowly building, not only for Revoutionaries vs Cipher Pol but because of personal reasons and resentment too...