I think you've got a great spread of classic dungeons there!
The only old one I would suggest is L-2: The Assassin's Knot (from the Lendore Isles series) for a change of pace from all the dungeon crawling. It's a convoluted murder mystery that will keep the characters guessing, designed for AD&D levels 2-5. It's the rare event-driven adventure among old school adventures, and is often overlooked by GMs. Also, few players I've run across are familiar with it, so it should be a surprise.
A retrospective about it:
https://www.wizards.com/dnd/article.asp?x=dnd/dx20001229b
DnDclassics link:
L2 The Assassin's Knot (1e) - Wizards of the Coast | AD&D 1st Ed. | Adventures | AD&D 1st Ed. | Dungeon Masters Guild
Conversion-wise, you're looking at almost entirely NPCs who fit the mold 1:1 with existing NPC stat blocks in the Monster Manual. The main villain, however, you have a decision to make: You COULD use a certain MM stat block for, though it won't be a direct 1:1 conversion and will be CR 9. Alternately, you could write up the villain's stat block from scratch using the DMG guidelines or PHB rules.
What I like about it is that because it's not a combat-driven dungeon crawl, it scales very well to whatever level you want to run it at. And it's short (30-pages) and generic enough that the GM can easily adapt it to his or her campaign. As a mystery, it's well designed because it seems like half the castle is evil alignment - plenty of scoundrels for the PCs to suspect guilty of the murder!
Oh man, Umbra! My favorite adventure ever
That's how I first learned about Chris Perkins too. Fabulous adventure.
