Regarding the poll, I voted for the LPB FH, but I wanted to make a case for Adori Zahard as well. I think it would be pretty strange if the portal Lyborick was guarding was the Lo Po Bia one.
Lyborick is strongly suggested to be on his ship, which comes from Z's Army. Why the LPB portal, which has been connected to the Nest since Ancient Times and is on a place not even Lefav or Yas know about, would be inside Lyborick's ship and be guarded by Lyborick out of all people?
Not to mention, if that's the LPB portal, then Evankhell and Kallavan will go to the exact same place. I find this a bit unlikely as well and Lyborick would need to have a strong backup to be able to hold his ground.
All the questions and strange things get perfectly answered if you assume that the portal Lyborick is guarding is not the one that leads to the LPB Mothership, but one that leads to the main stronghold of the Zahard Empire. While if it is the LPB one, it's all very very strange.
Adori at the same time also has reasons to oppose Baam's story (she's a Zahard fanatic) and should be someone Maschenny can't handle even if she wants to.
There's a set-up from the Three Orders:
1. Destroy FUG: Some really important figures are on the Nest (Slayers and Elders).
2. Destroy the Regulars riding the Hell Train: The main people targeted are all at the Nest (above all, Baam is there).
3. Destroy the Po Bidau Family (hidden): Po Bidau Lyborick Khun exists.
She could be appearing at the Nest to fulfil content from the Three Orders simultaneously.
I still think "The One in a High Place" portrayal fits more for the FH than it does for Adori, but I also believe Adori showing up has a pretty legitimate basis and reasoning (even if at the end of the day it's all headcanon).