Since (Ein) Meirvale has been retconned into Stitches / Merryvale, where possibly could be the Heimthor Mount?
Out of the map?
Retconned into Sunspire?
(Remember, in Summerset chapter the Arena names were sometimes changed to look like a past-future misspelling (Thorheim Guard renamed into Tor-Hame-Kard
I haven't got the time to play though the chapter yet but while I was wandering a bit there, I was surprised to find no mention of it.