I'm collecting a YouTube playlist of the fastest WoL brutal individual level runs that I could find.

https://www.youtube.com/playlist?list=PLid3-p_QYB9AyWQ6frHyu_dfvEV8t4Ori

These include some not on the leaderboard https://www.speedrun.com/sc2wol/individual_levels

Please let me know if any of the records in the playlist have been beaten or anything is inaccurate.

They nerfed Zeratul's blink, making Freezard's echoes of the future run unrepeatable.

What's the best Echoes of the Future run done after the nerf?

Not sure what the fastest Echoes run is but Freezard's can most likely be beaten with Chinese voices

Whispers of Doom can't be repeated either btw

I had no idea changes in multiplayer affected campaigns. That's really bad design as some random nerf/buff to multiplayer might make a mission almost impossible to play. Is it possible to play different versions?

I think it's not multiplayer balance challenges affecting campaign, but changes that developers made specifically for the campaign. I don't know about downpatching. Are records allowed on any patch?

No point to play on an older patch. The run won't be eligible if it can't be replicated on the latest patch.