Prepping for the Mind Flayer ambush in Hall of Harsh Reflections.
1) The conversion misses the DC10 Survival check at the end of this section of text on page 51:
Finding the entrance to Zyrxog’s domain by tracking the drow requires 1d6+3 DC
25 Survival checks by a character with the Track feat. Each check takes 1d3 hours of
exploration. A DC 20 Knowledge (nature) check is enough to reveal that Beggar’s
Gold often grows in sewers where runoff from smithies or forges can be found.
With this information, the Survival check to Track them drops to DC 15.
A DC 20 Gather Information or Knowledge (local) check is enough to locate the
smithy called Cold Forge. The owner of this smithy, a foul-mouthed man named
Crusty Patten, is unaware of the danger that lurks under his establishment.
If the party is searching for phosphorescent mold, finding Zyrxog’s domain
only requires a DC 10 Survival check without the need of the Track feat.
I understand these paragraphs right until the last one. DC25 survival to track the drow. DC20 knowledge check to understand that the mold grows near smithies reduces the survival check to DC15. But then if you're just searching for the mold, the check drops to DC10? So if you're following the drow (or reverse following them, given that they are probably dead), it's really hard. If you know about the mold, following the drow is a bit easier. But if you ignore the drow entirely, and just search for a secret door near mold patches, it's much easier?
2) Also, do the two drow thralls in the Mind Flayer ambush still have their potions of cure moderate wounds?
3) M5 Chattel Pen
I assume the hp and damage of the zombies increased due to being EL3, but it feels strange to have human zombies with more hp than allowed in the MM. Couldn't there be 1.25 zombies per PC instead?
4) M9 Laboratory
An ABOLETH?! That's more dangerous than the mind flayer boss!
Does it get legendary abilities? It can enslave as well? Yikes.
No lair abilities?
5) M11 Museum
Typo in the first sentence under "Treasure".
You didn't think permanent INT and WIS loss was reasonable for the Grimoire?
Periapt of Foul Rotting is a bit nicer too - things were hardcore in 1e!
You should indicate that "a kyton's chains" means Chain Devil (MM72)
You missed converting the tiny animated object (book wrapped in chains).
6) M13 Cathedral of the Mind
You don't list an equivalent to the unhallow enchantment on the room.
You also don't indicate if you think Zyrxog should have any of the magic items listed. I'm not sure what a "lesser empower metamagic rod" does, but I can kind of guess. Some of the other items seem less relevant (boots of elvenkind?) while others more so (necklace of fireballs!).