To me, the most intriguing question is this: who instructed those guys to pull Saul over, take the money and kill him?
We know it wasn't Gus, as Mike would know about it and then wouldn't kill them all.
If it was Lalo, it seems odd that he would have the cousins make the hand-off and then have another group of men pull Saul over, take the money, and then kill him (which was the intention before Mike made the save). Plus, if it was Lalo, he and the rest of the Salamanca crew would go ape shit once they found out that their men were killed and that the lawyer still has the money. That would put the nail in the coffin of both Saul and Kim, and we know Saul isn't going anywhere.
Could Nacho have been behind it? Not sure what his end game would be, though, and it would seem odd for him to have ordered the move and the execution of Saul.