If my maths is right, the Runestone by itself is worth at least 15 interest, 24 if it triggers the Citadels "Lustrian Magic" affinity, plus an additional 3 if we bring in the Arabyans.
Relevent tags: History, Magic, Necromancy, Lustrian Magic?
Base: 3 (centrepiece)
Awakening: History (3), magic (3)
Arabyan Academics: magic (3)
Harkon: necromancy (9)
Citadel: Lustrian magic (9)
The sea beasts we already have would add five points, for a round 20, but we'd loose the same number of points from the Dangers exhibit, so that washes out.
If the Runestone does count as "Lustrian magic"—I'm being a bit cautious here because I'm unsure whether the Pieces of Eight are Lustrian enough to qualify—then that would earn us two goodwill by itself (we need 22 points).
If it doesn't, then pulling in the Arabyans will net us the difference, as we'd get 3 from the Runestone and 8 from our current exhibits (age 3 and magic 5) for an extra 11 points.
In short:
Runestone, no elves, no Arabyans: 15 points
Runestone, elves, no Arabyans: 24 points
Runestone, no elves, Arabyans: 18 + 8 points
Runestone, elves, Arabyans: 27 + 8 points
As such, I think we should create the Runestone exhibit and send out marketing emails to some of our old students—that will net us enough points with or without the elves to grab two goodwill, which we can spend next turn on new contacts and crew, or just hit people with the magic "you like Lustria now" beam.
The third action should be acquiring magical relics of some kind—either through New Huatl or through Aelsabrim—to set us up the following turn to build a proper magic exhibit.
I'm leaning towards Aelsabrim, to clear out her warehouse of stolen Lizardman stuff and build something around the palaquin we have.
[] Plan: Magical Miscellany
- [] Create Exhibit (the Tide of Skjold, bearer of one of the Pieces of Eight: Runestone, all sea beasts)
- [] Acquire relics (via Aelsabrim): Magical Relics
- [] New Audience - Arabyan Academics
This will earn us either 26 or 35 points, enough to clear the next two goodwill thresholds.