Hi,

1. Mythran sells 6 spells and 1 scroll if I read ultima wiki correctly:
wiki.ultimacodex.com/wiki/Mythran

But in my actual savegame Mythran only sold me Confusion Blast and Meteor Shower. After that he only wants to sell me Ethereal Travel. He sells me Ethereal Travel 20 times in a row. I have enough money even to purchase the 1000 obsidian Devastation, but he doesnt offer me that spell.

I have all 4 titan items and the obsidian spire, could that cause a problem? Mithran only wants to send me in the Ether.

2. Is it possible to get the addon Lost Vale somewhere?
wiki.ultimacodex.com/wiki/The_Lost_Vale

The addon was finished 1994 and I want it so badly. They wrote at ultima wiki: The project was not archived and its data was eventually lost.[1] Only some screenshots, plot documents and the box design, which was later confirmed as genuine, survived.

Also the Lost Vale plot documents:
gallery.ultimacodex.com/the-lost-vale-plot-documents/#

3. A tip for players who wants to finish the ghost quest but Jenna is angry on your avatar like she is on me:
http:\\www.file-upload.net/download-9256283/U8-ghost-quest.jpg.html
Its a pic showing a huge stack of items (wood, bones and more) in front of the closed door at the dungeon.

Can't help with #1, but you can read something about #2 here - http://www.gog.com/forum/ultima_series/ultima_viii_the_lost_vale

Thats a good answer at #2, thank you for that. : )

Mythran is supposed to offer you one spell after another (Confusion Blast, Meteor Shower, Summon Creature, Call Destruction, Devastation, Ethereal Travel), once you've advanced far enough in the game. My guess is, that you've advanced "too far" in the main story, so that Ethereal Travel is triggered and the missing spells are skipped.
Go back to an older savegame and check Mythrans offers again. I doubt there's a fix once Ethereal Travel is offered.

Yes, seems to be that problem. Older savegames are working where I dont have enough money. I supposed to farm as much money as I can and was hunting the titans at the same time, but now I will not be able to get the spells with my late game character. These bugs are a bit annoying.

Yes, they are. What you can do is visiting theUltima VIII Cheat Room, which contains among weapons, shields etc. a scroll of every spell. As long as you only take the missing spells from Mythran, I wouldn't consider it cheating, as the game mechanics "cheated" on you in the first place ;-)