There are different categories of members of the assembly (ἐκκλησίᾳ which is usually called church in our NT translations, except that the physical building is usually referred to as a συναγωγὴ 'Synagogue'), a few of which the early church that the heterodox authors were not concerned with include:
- non believers
- "idiot" or "initiate" refers to a new or potential members, somebody who does not know church customs
- rectors (literally ship pilot) who administer the daily affairs of church property
- helpers or partakers
None of these roles are part of the church spoken of by Marcion's Paul. They are products of a later time,
and not necessarily of a different Christianity. In fact the term elders (πρεσβυτέρων) even for the Jews, quite possibly never occurs in Marcion, as the one citation in Luke 9:22 by Tertullian AM 4.21.7 (dicens quia oportet Filium hominis multa pati et reprobari a senioribus et principibus sacerdotum et scribis et occidi et tertia die resurgere) is contradicted by Epiphanius P42 (δεῖ τὸν υἱὸν τοῦ ἀνθρώπου πολλὰ παθεῖν καὶ ἀποκτανθῆναι καὶ μετὰ τρεῖς ἡμέρας ἐγερθῆναι) who lacks mention (twice!) of "and be rejected of the elders, and scribes, and priests," something Marcion would find no reason to object. In this rare case I side with Epiphanius over Tertullian, as the addition is an embellishment and Tertullian may simply have been sloppy and quoted the Catholic text. There is no clear attestation in either Luke 9:3 (no parallels for the phrase "elders of the Jews in either Matthew or John), or Luke 20:1 - but I must admit the common text of Mark 11:28/Matthew 21:23 contain οἱ πρεσβύτεροι so its possible it appears once in Marcion, but then again perhaps Luke harmonized Marcion's text. This seems even more clear in 22:52, when you remove the text of 22:49-51 (Epiphanius P42) which was not in Marcion, then it's clear it was a crowd that comes out to seize him - the same crowd Jesus addresses in Matthew 26:55. Clearly the Luke expanded the account, and added the elders, scribes, and chief priests to the account. In 22:66 we have the marker Καὶ ὡς ἐγένετο ἡμέρα alerting us to Luke's editorial hand, so it's no surprise the οἱ δὲ ἀρχιερεῖς καὶ ὅλον τὸ συνέδριον of Mark 14:55 (also Matthew 26:59) was expanded to include scribes and elders of the people συνήχθη τὸ πρεσβυτέριον τοῦ λαοῦ, ἀρχιερεῖς τε καὶ γραμματεῖς, καὶ ἀπήγαγον αὐτὸν εἰς τὸ συνέδριον αὐτῶν, (note also the Lucan τε καὶ which is never present in Marcion) who simply don't belong on the council. None of these instances of are attested in Marcion.
I do not think the omission is out of any theological difference, as Marcion saw the scribes of the Jews filling the role of the Orthodox in searching the Scripture (the LXX) for verses that seemed to support their view of Jesus. Rather the omissions can be traced to the command structure of Marcion's church, which did not have a place for any positions of authority other than the Apostle/Bishop and Deacons. This will become clear as we examine more evidence.
And these changes are significant, starting with the role of the bishops (ἐπισκόπους), where the difference from Marcion's era is less in function than in number. (The impact of bishops upon church organization in the 2nd century I will cover in a later post.)
The need for κυβερνήσεις and the ἀντιλήμψεις who likely worked for them tells us we are now dealing with a larger organization. It is now layered with a Bishop who is in charge of an church assembly (still likely an ἐκκλησίᾳ rather than a συναγωγὴ), who now delegated operational tasks to church administrators (rectors) κυβερνήσεις who had their own clerical help ἀντιλήμψεις. Marcion's church was much simpler and his Paul repeatedly made decisions ranging to minutia without regard to underlings (I will go over this in my discussion of the office of Bishop in another post). To require this extra layer of workers who are not deacons or bishops, implies the church has now grow somewhat large, and numbers into the many hundred or even thousands under any given bishop. So now the bishop needs significant operational organization. We are long past the initial evangelical phase to require these.
We see the lateness of the Catholic version again in the changes to the congregation and worries about how the church appears to those who are initiates (ἰδιῶται) and even to unbelievers (ἄπιστος). When the Marcionite version was written the theology of 2 Corinthians 6:14 was in force, Μὴ γίνεσθε ἑτεροζυγοῦντες ἀπίστοις,  there was to be no mixing of Christians and non-believers. Marcion was concerned with creating a "pure" and preferably chaste congregation (see my reconstruction of 1 Corinthians 5-7).
But in the Catholic version, the concern has shifted. What I wrote concerning verses 7:12-17 is worth reading here, especially since the consequences of an interfaith marriage are discussed:
Verses 7:12-17 are concerned with matters from a much later time. The discussion is about marriage with non-Christian spouses, and whether the children produced in such marriages are considered members of the Church, and how to handle divorces. This is in direct contradiction to verse 7:11 where divorce is prohibited, revealing a later doctrine consistent with Orthodoxy. More direct evidence from Tertullian (AM 5.7.8) on 1 Corinthians 7:39 directly prohibiting marriage with non-Christians, and he assures us that Marcion’s Paul does not allow it:
Pusillum deum affirmas tuum, Marcion, quem in aliquo coangustat tempus creatoris. Gerte praescribens tantum in domino esse nubendum, ne qui fidelis ethnicum matrimonium contrahat, legem tuetur creatoris, allophylorum nuptias ubique prohibentis.
While declaring your God, Marcion, who is any way confined into the creator’s time. Indeed, in prescribing marriage only the lord, that a believer may not marry a Gentile, defends the law of the creator, prohibiting all marriage with aliens.
Over time the theme within the Church of allowing conditional divorce grew. By the time the Gospel of Matthew was written, the condition of adultery was an acceptable grounds for divorce (Matthew 5:31-32, 19:9). Similarly the argument is tied to Moses (19:7-8, referencing Deuteronomy 24:1-4).
As you can see my conclusion is this was written much later, less the result of a theological change than a generational one, where growth and conversion led to this condition.
 2 Corinthians 6:14 is implied as present in Marcion from DA 2.12 when Adamantius quotes τίς κοινωνία φωτὶ πρὸς σκότος. This requires the preceding phrase quoted here. It is also consistent with Marcionite demands of complete separation from the world, as 1 Corithians 5:6 points out "Do you not know that a little leaven, leavens all the mixture?" οὐκ οἴδατε ὅτι μικρὰ ζύμη ὅλον τὸ φύραμα ζυμοῖ; See the following verse quoted by Tertullian which continues the thought AM 5.7.3 Expurgate vetus fermentum, ut sitis nova conspersio, sicut estis azymi.