So, for me, using Foundry. I just updated to the latest version of the PDF to Foundry importer (1.7.1), then imported the adventure, and then imported the interactive maps file.
The result was I got two folders of scenes:
Abomination Vaults - Ruins of Gauntlight
Abomination Vaults - Ruins of Gauntlight (Interactive Maps)
Both folders have the HQ maps from the map files. The first folder scenes have all the walls and everything on them. The only issue is that the Level 4 map didn't import for some reason (only have the version from the adventure pdf).
Didn't have to do any fooling around with replacing maps, or copying the walls or anything.