"If these things exist and you CAN’T prove them using evidence in an unbroken string from Apostle to Church Father, you are assuming."
The first question would be, is one assuming reasonably, or is one assuming unreasonably?
I have to start with this, because there are many lacunae in the history of the Chosen People of the OT. For instance, there were approx. 200 years between the book of Ecclesiastes (~1000 BC) and the prophets Joel and Amos (~800 BC), 400 years between Malachi (~400 BC) and Matthew (~45 AD). The book of Psalms, which is a hymnal collection, may have nearly a thousand-year gap between the first-written group and the last-written, from 1400 to 450 BC.(All these dates are necessarily approximate, because while the canon of scripture is indeed inspired, the placement of the books is not.)
Many more gaps of 50 years, 100 years or more could be attested by scholars. I’ll let them debate it among themselves as long as they don’t come to fisticuffs.
It is a reasonable assumption that the Chosen People were still existing, still praying and singing, and still carrying on some form of national and organized religious life during every period of their known history starting with Abraham (we can call this the Hermeneutic of Continuity).
On the other hand, it would be unreasonable to assume that there is no continuity, and that each of the OT books marks a disjuncture and a re-invention of Israelite existence. (Call this the Hermeneutic of Rupture.)
The same is true in the life of the Church. A reasonable examination of the texts is meaningful only if you realize that there is a cultural/historical personal transmission process underneath it. The texts outline, but do not comprehensively catalog, the cultural history behind them.
It's like looking at a chain of islands in the Pacific which look like separate peaks, but which are actually the tops of a single, submerged mountain range. I've had this experience looking at parts of the nearby Unaka range (Southern Appalachia) when the "hollers", valleys and coves were all shrouded with mist, so that it looked like there were separate mountain ridges floating in the sky. But they are in fact continuous at the base. Many ridges, one range.
I'd say there are two ways to establish the links you are looking for. One is archaeology (a method of discovery/recovery) and the other is continuity (a method of seamless, lived succession).
The first ones we want to look at are the earliest Church Fathers, (within two generations of the Twelve Apostles of Christ) --- also called the Apostolic Fathers since they were of the second generation after the Twelve, and taught by the Twelve.
FIRST CENTURY (writing before 100 AD)
The biggies are Clement of Rome, (died in 99 AD), who was a contemporary of the Apostles; and Ignatius of Antioch (d. 107 AD), a contemporary of most of the Apostles. In addition, the Didache (written sometime between 50-100 AD) is dated in the same generation as the writings of these Apostolic Fathers (Clement and Ignatius) although its author is unknown.
SECOND CENTURY (writing before 200 AD)
Polycarp of Smyrna (d. 155 AD), Justin Martyr (d. 165), Irenaeus (d. 202), Clement of Alexandria (d. 215(.
THIRD CENTURY (writing before 300 AD)
Shepherd of Hermas (early 200’s), Clement of Alexandria (d. 215).
Those are some of the visible mountain tops. Then you look at the base: the elements which are known, not because they are recovered, but because they have been continuously lived. That would be mostly liturgy and the things that separately comprise or surround liturgy: essentially, texts, hymns, and rubrics.
There’s a couple good introduction here Church History Though the Liturgy.
Plus, grab onto and study the Liturgy of St. James. This goes all the way back to James, the “brother” of the Lord and patriarch of the Jewish Christians of Jerusalem before the destruction of the Temple. First celebrated in around 60 AD, it is the oldest form of the Divine Liturgy used continuously, and still in actual Church use.
That’s enough for now. Looks like I'm outlining a dissertation?!
I am happy to answer this sort of question, because I never fail to learn something new that just delights me.
This may take you awhile. Happy Reading!
But of course, assumptions remain assumptions when they are without evidence. In this discussion, which has been wide ranging, you are not bringing forth evidence that supports anything about Jesus' brothers and sisters, perpetual virginity or as far as I remember (long day) any other topic. In the end an assumption may be right or wrong, but it is not known which it is without evidence.
Obviously there were gaps in Hebrew revelation, but in the end, it was all inspired revelation that is augmented with non-inspired history and other sources. Those other sources are very, very interesting, but not inspired.
"Clement of Rome, (died in 99 AD), who was a contemporary of the Apostles; and Ignatius of Antioch (d. 107 AD)" OK, bring forth the evidence from these two sources and let's take a look! They wont change the utter absence of inspired evidence, but let's take a look.
From your St. James link: "This Liturgy is the oldest Eucharistic service in continual use. In its present form, it's believed to go back to the Fourth Century, and some variation of the Liturgy likely dates back much earlier, perhaps as early as 60 A.D. (making it older than much of the New Testament). It's classically ascribed to St. James, the Bishop of Jerusalem, and has special prayers for the Church at Jerusalem. and what we have here is probably pretty close to what a Jerusalem Christian would be praying on an ordinary Sunday in the early 300s."
Believed, Fourth Century, Likely dates back, perhaps as early, ascribed, is probably pretty close, in the early 300s.
Frankly, it is indeed interesting, but there are no Christian priests in the Church recorded in the New Testament as an office. There is no evidence of a belief in transubstantiation in the early church in Acts or the Epistles. For those reasons and the outright admission that there is not an unbroken chain between the NT church and this form of liturgy, it is not definitive. Much was obviously added in later centuries. Still, it is interesting.
In closing, I always appreciate your good spirit, despite our disagreements.