That's simply the way myths evolve. Whether it's the Old Testament David, the Greek Heracles, or Robin Hood - over time myths attach themselves to the most popular character in the pantheon.
No, not really. At least not if you're talking about about legendary histories of the sort that mix myth, fable, folktale, and fact in recounting the early history of peoples/nations/cities/religions. Those kinds of historical mythologies (and I would consider the 'early church histories' from Gods of Harn
to fall into that category) tend to assign different roles/acts to different figures throughout time-- and then organize them into a coherent chronology. Thus, in the Hebrew Bible, it was Abraham with whom the divine covenant was made, Joseph who went to the land of Egypt (the great 'enemy nation'), Moses who later liberated the Hebrews from Egypt, Joshua who then conquered the promised land, a whole bunch of various "judges" who fought wars against later national enemies, Saul who established the monarchy, David who established the lasting royal line, Solomon who was the greatest/wisest king, etc. Or, in Roman history, it was Aeneas who led the future Romans from Troy to Italy, Romulus who actually built the city of Rome, Numa who gave the romans their laws and civil institutions, etc.
Moralin is simply "that character" for the Agrikans. Whether the real Moralin was the conqueror of Lysara or the wandering disciple who wrote the Balefire Chronicle is hard to tell.
Certainly, the exact nature of Moralin's activities-- or whether there even was a historical 'Moralin' in the first place-- is unknowable. But, my point is that the idea that he "established Lysara as a key center of Agrikan worship and power" seems radically at odds with everything else we're told about him (he was one of Ilpylen's original disciples and spent his life as a wanderer). It also seems at odds with the what we're told-- even elsewhere in the Venarive module
-- about the cities of Azeryan region not really being founded until 1-2 centuries after TR, and Agrikanism becoming prominent after that.
Now, it's true that legendary histories are flexible with time, lifespans, historical distance, roles etc. But they do show some awareness of chronology (in fact, they exist, in part, to organize legends into a coherent chronology). And the idea Moralin was both a disciple of Ilpylen and a leader of one of the wandering bands who comprised the earliest form of the 'church'-- and the one who made Lysara an Agrikan enclave-- seems anomalous, even in the realm of mythicized history, given how far these are apart. This would be like having Moses conflated with David-- or Aeneas conflated with Lucius Junius Brutus-- or Leif Erickson conflated with George Washington.
Personally, I believe it was probably the former. Most likely, as Lysara spread its influence it embellished the story of their founder. I can almost imagine the high priest (and eventually the pontiff) opening each octennial Games with a recitation of the achievements of his predecessor, and every eight years the list gets a little longer.
That last item that *is* a distinctive character of these kinds of legendary histories-- a desire to trace a line connecting oneself to the (semi-)mythical founders. However, establishing this kind of historical 'genealogy' does not require (or even usually entail) a conflation of all former heroes into one. In fact, it usually works in the opposite manner, by carving out different and distinct roles for all the great national/civic/religious heroes, but then carefully constructing connections between them, so that an unbroken line of continuity can be traced from the great founders to the present. This may be done by tracing connections of blood (thus all the 'begat' chapters in the bible), or by tracing out a succession of rulership, or tutelage, or some other kind of connection.
So, to address your point, I certainly can see the Lysaran pontiffs wanting to trace their authority/origins back to Moralin (and thus also to Ilpylen, and Agrik himself). And I can see legendary histories establishing such a connection. But... I don't see these as presenting Moralin as a founder/conqueror of Lysara per se, since that seems to be so contrary to everything else that's told about the early church-- and pre-TR Azeryan.
Might such histories tell that Moralin, in his wanderings, passed through Lysara? Sure. In fact, almost certainly.
That he built a cairn there? Absolutely.
That the sacred octagonal chamber in the pontifical temple is built on the site of this cairn? Of course! (In fact, it probably contains a pile of stone that are said to be Moralin's original cairn.)
That this cairn was especially important-- and that a group of priests (descended from Moralin's initial band) devoted particular attention to its maintenance, and that the present-day 'church' is descended from this band? Duh!
That Moralin the Wanderer retired from wandering and came to rule the city that would be Lysara, establishing it as a base of Agrikan power-- 1600 years before there were even cities in this part of the world? Um... no. That seems just too much. Besides, there are going to be local Lysaran/Azeri heroes who need to have their roles celebrated into this mythic history.... Moralin's got more than enough here with being one of Ilpylen's disciples, the author of the Balefire Chronicle, and being the leader of one of the wandering bands of cairn-builders. Those Azeri natives need their own mythic credentials established in the church history as well.