What the Recognitions say about Saul attacking James and his followers (including priests) is in keeping with what Josephus says about a Herodian named Saul who is mentioned right after the James passage in Ant. 20.9.4:
Costobarus also, and Saulus, did themselves get together a multitude of wicked wretches, and this because they were of the royal family; and so they obtained favor among them, because of their kindred to Agrippa; but still they used violence with the people, and were very ready to plunder those that were weaker than themselves.
Cf. Rec. 1.70:
... one of our enemies entering the temple with a few men, began to cry out ... While he was thus speaking, and adding more to the same effect, and while James the bishop was refuting him, he began to excite the people and to raise a tumult, so that the people might not be able to hear what was said ... he began to drive all into confusion with shouting, and to undo what had been arranged with much labour, and at the same time to reproach the priests, and to enrage them with revilings and abuse, and, like a madman, to excite every one to murder ... he first, seizing a strong brand from the altar, set the example of smiting. Then others also, seeing him, were carried away with like readiness. Then ensued a tumult on either side, of the beating and the beaten. Much blood is shed; there is a confused flight, in the midst of which that enemy attacked James ...
And this fits with what Josephus and the Talmud say about this era.
Ant. 20.8.8:
And now arose a sedition between the high priests and the principal men of the multitude of Jerusalem; each of which got them a company of the boldest sort of men, and of those that loved innovations about them, and became leaders to them; and when they struggled together, they did it by casting reproachful words against one another, and by throwing stones also. And there was nobody to reprove them; but these disorders were done after a licentious manner in the city, as if it had no government over it. And such was the impudence and boldness that had seized on the high priests, that they had the hardiness to send their servants into the threshing-floors, to take away those tithes that were due to the priests, insomuch that it so fell out that the poorest sort of the priests died for want. To this degree did the violence of the seditious prevail over all right and justice.
Ant. 20.9.2:
... he [the high priest] also had servants who were very wicked, who joined themselves to the boldest sort of the people, and went to the thrashing-floors, and took away the tithes that belonged to the priests by violence, and did not refrain from beating such as would not give these tithes to them. So the other high priests acted in the like manner, as did those his servants, without any one being able to prohibit them ...
Pes. 57a:
... their servants strike the people with clubs, and otherwise act inappropriately.
And that some of James' followers are said to be priests fits with what Acts 6:7 says:
The number of disciples in Jerusalem increased rapidly, and a large number of priests became obedient to the faith.
That the enemy Saul in Recognitions 1.70 (who "began ... to reproach the priests, and to enrage them with revilings and abuse and, like a madman, to excite everyone to murder" and used "a strong brand from the altar" to "set the example of smiting") is Paul and that he was a servant of the high priests (as per the Talmud) is clear from what follows in 1.71:
... that enemy had received a commission from Caiaphas, the chief priest, that he should arrest all who believed in Jesus, and should go to Damascus with his letters, and that there also employing the help of the unbelievers, he should make havoc among the faithful; and that he was hastening to Damascus chiefly on this account.
And even after his conversion Paul remained a hothead and verbally abused Cephas "to his face ... in front of them all" in Gal. 2:11-14:
When Cephas came to Antioch, however, I opposed him to his face, because he stood to be condemned. For before certain men came from James, he used to eat with the Gentiles. But when they arrived, he began to draw back and separate himself, for fear of those in the circumcision group. The other Jews joined in his hypocrisy, so that by their hypocrisy even Barnabas was led astray.
When I saw that they were not walking in line with the truth of the gospel, I said to Cephas in front of them all ...
And he continued to brag about his prowess in 1 Cor. 9:25-26:
Everyone who competes in the games trains with strict discipline. They do it for a crown that is perishable, but we do it for a crown that is imperishable. Therefore I do not run aimlessly; I do not fight like I am beating the air.
So I am inclined to take what the Recognitions say about Saul seriously and to see Josephus' Saul as Paul. Not only do these details fit, but how many Herodians named Saul who used violence against "those who were weaker than themselves" do you suppose there were during this time? Josephus mentions only one, and Christian writings mention only one.