" And like I said, we have no Eastern church fathers before the 3rd century"
You've lost me here. What about +Ignatius or +Polycarp just for starters?
St. Irenaeus speaks of a certain number of letters written by Polycarp,[8] but we have only his letter to the Philipplans, written on the occasion of Ignatius' sojourn among them.
We have Polycarp's reply, written probably soon after the death of St. Ignatius,[9] but the entire text is extant only in a mediocre Latin translation. All the Greek manuscripts which have reached us stop towards the end of ch. ix. Fortunately Eusebius has transcribed the whole of ch. ix as well as ch. xiii, - the two most important chapters.[10]
The oldest collection of the writings of St. Ignatius known to have existed was that made use of by the historian Eusebius in the first half of the fourth century, but which unfortunately is no longer extant
http://www.earlychristianwritings.com/tixeront/section1-1.html#polycarp
There are, in all, fifteen Epistles which bear the name of Ignatius. These are the following: One to the Virgin Mary, two to the Apostle John, one to Mary of Cassobelae, one to the Tarsians, one to the Antiochians, one to Hero, a deacon of Antioch, one to the Philippians; one to the Ephesians, one to the Magnesians, one to the Trallians, one to the Romans, one to the Philadelphians, one to the Smyrnaeans, and one to Polycarp. The first three exist only in Latin: all the rest are extant also in Greek.
It is now the universal opinion of critics, that the first eight of these professedly Ignatian letters are spurious. They bear in themselves indubitable proofs of being the production of a later age than that in which Ignatius lived. Neither Eusebius nor Jerome makes the least reference to them; and they are now by common consent set aside as forgeries, which were at various dates, and to serve special purposes, put forth under the name of the celebrated Bishop of Antioch.
But after the question has been thus simplified, it still remains sufficiently complex. Of the seven Epistles which are acknowledged by Eusebius (Hist. Eccl., iii. 36), we possess two Greek recensions, a shorter and a longer. It is plain that one or other of these exhibits a corrupt text, and scholars have for the most part agreed to accept the shorter form as representing the genuine letters of Ignatius. This was the opinion generally acquiesced in, from the time when critical editions of these Epistles began to be issued, down to our own day. Criticism, indeed, fluctuated a good deal as to which Epistles should be accepted and which rejected. Archp. Usher (1644), Isaac Vossius (1646), J. B. Cotelerius (1672), Dr. T. Smith (I709), and others, edited the writings ascribed to Ignatius in forms differing very considerably as to the order in which they were arranged, and the degree of authority assigned them, until at length, from about the beginning of the eighteenth century, the seven Greek Epistles, of which a translation is here given, came to be generally accepted in their shorter form as the genuine writings of Ignatius.
Before this date, however, there had not been wanting some who refused to acknowledge the authenticity of these Epistles in either of the recensions in which they were then known to exist. By far the most learned and elaborate work maintaining this position was that of Daillé (or Dallaeus), published in 1666. This drew forth in reply the celebrated Vindiciae of Bishop Pearson, which appeared in 1672. It was generally supposed that this latter work had established on an immoveable foundation the genuineness of the shorter form of the Ignatian Epistles; and, as we have stated above, this was the conclusion almost universally accepted down to our own day. The only considerable exception to this concurrence was presented by Whiston, who laboured to maintain in his Primitive Christianity Revived (1711) the superior claims of the longer recension of the Epistles, apparently influenced in doing so by the support which he thought they furnished to the kind of Arianism which he had adopted.
But although the shorter form of the Ignatian letters had been generally accepted in preference to the longer, there was still a pretty prevalent opinion among scholars, that even it could not be regarded as absolutely free from interpolations, or as of undoubted authenticity. Thus said Lardner, in his Credibility of the Gospel History (1743): "have carefully compared the two editions, and am very well satisfied, upon that comparison, that the larger are an interpolation of the smaller, and not the smaller an epitome or abridgment of the larger.... But whether the smaller themselves are the genuine writings of Ignatius, Bishop of Antioch, is a question that has been much disputed, and has employed the pens of the ablest critics. And whatever positiveness some may have shown on either side, I must own I have found it a very difficult question."
This expression of uncertainty was repeated in substance by Jortin (1751), Mosheim (1755), Griesbach
http://www.earlychristianwritings.com/info/ignatius.html