Vern and I were discussing this loose end, and we came up with a suggestion for a solution:

• Epidemic in Ranyon-ruhn stays as-is, though Ratagos will no longer send the player to Necrom upon completion. Instead, he suspects Vampires / a Molag Bal cult as before.
• Either
  • Ratagos sends the player to the cult's lair directly or
  • the spirit of a Waking Guide from Necrom appears and requests assistance liberating a newly-deceased ghost from the cult - revealing its location. The Waking Guides are the Temple folk that are brought to the brink of death and then use the opportunity to leave their bodies behind in Necrom and wander the land in spirit form, seeking out lost / wayward / deranged / cursed souls that can't navigate on their own anymore and guide them to Necrom. Clearly the Waking Guides would have difficulty shepherding souls back to Necrom if the location is infested with baddies, so a corporeal solution is required, and Ranyon-ruhn happens to be close by in an area where Temple resources are otherwise scarce.
• Player goes to the lair (i1-72-Tel) and kicks some vampire cultist ass.
• Player retrieves the remains of the cult's victim(s), maybe has a chat with the spirit, and returns them to Necrom (Bradys Hlaalo is probably a good contact point here, as overseer of the Charnelworks).
• Player has demonstrated an aptitude for getting their hands dirty and solving things Necrom can't fix remotely. Necrom can then refer the player to Almas Thirr, as an alternative route to steer the player towards the Speaker for the Dead line. 

If this is an acceptable solution I wouldn't mind claiming this.

quick edit: I am envisioning Bradys Hlaalo as the go-to guy for the initial, lower-level, Necrom Temple quests, so directing the player to him also sets up a useful segue into future Necrom Temple quests. Two birds one stone.

I've been taking a second look at exactly what the Ranyon-Ruhn Temple line entails, what this interior looks like, and how to reconcile everything.

The Ranyon-Ruhn Temple quest line leans very heavily on shady goings-on, attacks and vampiric infections. This was originally meant to lead into a confrontation with a joinable cult of Molag Bal. The interior linked here was built specifically to house that cult, and was to link to the Ruinous Crypt north of Llothanis. It is large, old, full of statues, and contains a bunch of custom books and literature relevant to the joinable aspect of the cult. Furthermore there are some questionable implementations to the int that wouldn't pass our current-day quality control.

Still, there is the glaring issue that the current RR Temple line is unfinished, ends on a cliffhanger, and tells the player to go to Necrom where there is no logical follow-up, nor would it be in any way logical for Necrom to offer a follow-up in the first place.

As far as I'm concerned, there are three possible ways we could go about this:

1. We discard the interior entirely, and simply settle for the Ruinous Crypt and the handful of vampires that already hang out in there.
2. We take the interior, remove the Inner Courtyard and connected Chambers cells, remove three superfluous Molag Bal statues, and connect the entrance to the Ruinous Crypt. Then we add some generic cultists, vampires and cattle, and call it a day. That gives is a relatively sizeable dungeon for the player to crawl through, with its worst excesses curbed.
3. We pretent it's 2009 and implement a joinable Molag Bal cult.

Number 2 is my prefered option, as the Ruinous Crypt is sort of small and a bit of a dungeon crawl could be a fun capstone to this old quest.

As for how this final quest would play out:

• The player at this point has had multiple run-ins with these vampires and their cultist buddies, even though it wasn't spelled out very clearly until right at the final quest, in which a bunch of townsfolk get infected with Porphyric Hemophilia.
• Ratagos reveals that he suspects a cult of Molag Bal is behind all these shady happenings. He directs the player to talk to the surviving infected townsfolk (if any) to find out who they were in contact with that might have infected them, and to ask the people of Llothanis about who Yishini (who was already turned into a vampire and died in an earlier quest) was in contact with. Teris Sevuro travels to Llothanis ahead of the player and can be met at the entrance to the town. Ratagos lends the player the Amulet of Seht's Warding, that the player retrieved during an earlier quest, for protection.
• Asking around reveals a common contact point between all four victims is some TravelingTraderPerson who peddles his wares in Llothanis and Ranyon-Ruhn. Currently staying in some location in Llothanis, probably The Water's Shadow Tavern.
• When confronted, TravelingTraderPerson panicks, attacks the player. If calmed, he will reveal that he was threathened by the cult to seek out targets for them. If killed, he'll have a note on him to the same effect. Either way, the player figures out the Molag Bal Cult operates out of the Ruinous Crypt.
  • The Water's Shadow also houses a crusader, Cama, who could offer the player to join them in exterminating the vampire lair. Why not. Bit of flavor and fun.
• The player and possible allies head into the Ruinous Crypt and kill everything in sight.
• Ratagos thanks the player, takes the Amulet of Seht's Warding back, and rewards them with something else that's nice.
• Patriarch-rank players can keep the Amulet of Seht's Warding, or later ask about it and receive it.
• The end.

Note: Why asked me to check permissions on this claim and make some edits to test site stuff. All of my "editing" on this is on their request.

Transferring to abby

Marked this down for Andaram Expansion (optional), as this would fit in with the little Telvanni and Necrom additions we've been making here.

Ready for review: My notes are here: https://docs.google.com/document/d/1srqFeS-xFbb3i3kWKpDuoTADObnFkhjUyj8R...

Note for the reviewer: Cleaning with tes3cmd seems to break some of the journal entries where the quest ID was renamed.