Cell: 4,-47
Medium-sized abandoned Ancestral Tomb. Full of undead. The top level is used as storage, the rest of the tomb is behind a barred door. Potential quest: The farmers living on the hill above ask the player to put the spirits to rest, as the tomb belonged to the family a long time ago.

Cell: 4,-47
The side building of a netch farm. I'd make it part storage/utility, but also have a slave sleeping there. Perhaps make the slave a bit better treated than usual, with a proper bed and a few humble belongings. De_p furniture.

Cell: 5,-47
This would be a sewer system. I'd keep it relatively direct and straightforward in layout, but parts of it might have caved in leading to a mix of cave and sewer pieces. This interior probably leads to the chamber of the lich inhabiting the stronghold, or at least close by, but the lich should probably not actually hang out in the sewers. I am inclined not to make the lich a necromantic moustache-twirling villain, but there could perhaps be one or two guardians in the sewers guarding that approach. Or perhaps a swamp troll has taken up residence.

Cell: 5,-47

Make sure to read the document on Chimer Strongholds.

Also, there's this line from a Thirr Valley meeting summary:
"Chimer Strongholds - one will be occupied by the Cult of Arius, the other will have a lich hidden deep within, will mostly be abandoned and infested with vermin, with a few slaves hiding in a dome at the top."

Cell: 4,-47
Small grotto, full of water plants. A swamp troll lives inside.