Iranian General Qassem Soleimani had zero reasons to travel beyond the border of Iran. He could have arranged for various meetings within Iran, or chatted with people via phone or even Skype. So this necessity to be in Baghdad? It really didn't exist.
In his mind, he had absolute run of the system, and didn't have a single worry about anyone.....not a single Iraqi, or American GI....was going to be a threat to his safety.
So you go down this list of bad-guys who were in this SUV convey, and it's a whose-who of dead or capture VIP bad-guy players in the region.
This being some type of meeting with Soleimani and his 'team'? That's really the only reason to have done this....but it's a meeting that you could have accomplished in Iran. Why bother making this a open failure?
How to play this out if you were Iraq? You'd ask the question of who ordered the general to come into Iraq....name the Mullah.