Hi Bobcat,
Broadly speaking, scholars accept 7 letters as genuinely by Paul. Since they are placed in order of their length, this is one argument agaiinst Hebrews.
Other writings incorrectly attributed to Paul includes the Pastorals (Timothy, Titus, and 2 Thessalonians), while Peter did not write either letter attributed to him, with 2 Peter, 2 John, 3 John, Hebrews and Revelation having great difficulty being included in the NT canon.
There were any number of Gospels, Acts, and Apocalypses circulating during those early centuries, and the decisions on which to accept was made by those having allegiance to Paul. Not that there has been universal acceptance of the 27 books.
In my view, the Judaizers would have been aligned with the Jerusalem Church, which was headed by James. Paul was at odds with the Jerusalem Church, to put it mildly.
Regards,
Doug