Everything we have so far points towards Dragon
Look at the ship front, it resembles a lot the shadow we have of the ship above in 1081
The only time we saw the ship, we saw a "DOOM" and an explosion that opened a path through the fire = wind.
Dragon literally used a wind blast on marines
What if Dragon was in the marines because of his father (Garp) and got the tattoo to cover the burning scar?
Dragon said to Luffy "the day will come when we shall meet", expecting him to meet him at some point (poneglyph?)
I am still pretty sure it isnt Dragon.
It makes no sense to me.
And as you posted, his ship doesnt have black sails.
It is someone else who still works for the WG.
He probably delivered RPG to MJ long ago.
I doubt he drags it with him on the ship.
It could be a clone of Xebec.
Clones dont have to necessarily have the same mind.