I'm getting a real Valley of Gwangi feel about this version of X1 in the campaign setting so I'm moving the isle down more into Baja California coast region. For 1870 this means that the isle of dread itself has some very dark & sort of sinister connotations for the locals.
This is an island of the lost & of castaways with a strong connection to the elemental plane of water. For my games these isles have a very nefarious history with several of my Lion & Dragon rpg games in the past. Strange otherworldly pirates praying on vessels off the English coast only to vanish when given chase. System wise with Castles & Crusades converting the Lion & Dragon rpg shouldn't be a problem at all. That means that on the isle of dread or my version of it there's a small colony of Albion castaways
All of this goes back to me running the U1 Sinister Secret of Salt Marsh modules. The Sea Wasp was actually a ship in my games belonging to the slavers. The alchemist wasn't simply a corpse but a lich who was operating in his old haunts for the slavers with connections to the local Deep Ones. Yes this flies completely in the face of U1 but it worked out very well at the time for the Castles & Crusades game I had going.
I used the Slavers organization like something straight outta of Palladium Fantasy or Rifts. I've done this repeatedly over the years & my players continue to use the various campaign histories tangled together. Why because they like me DMing Castles & Crusades like a free wheeling Rifts game & I'm perfectly happy to do so. More as this as it develops tonight.
Tegel Manor is going to cross over all of this material coming up depending upon how the PC's go with the adventure elements.