Hi Andrew Scott
The first file listed has no file extension. It does not appear to be an LS4, and may be one of four files used for Lumion models.
I am able to open the .sva to see the scene and the clips and effects needed for creating videos are there.
However, as you noted, not all files are present for the project.
The options depend on access to the old architects PC and user files.
If both the old and new architect are working from the same PC, then the new architect should be able to just continue where the last one left off. As the new one will have a different Windows Profile, s/he will sign in under a different name, which will result in a different set of User data files in My Documents. Easiest is to sign in under the old architects profile (if possible).
If from the same office but different PC's then (pending access) all files (including source model files - exported from Revit or SketchUp etc) can be copied to the new architects PC.
If simple access is not available then, you need to get the following files.
A) if the architect used Lumion v4 Pro, then s/he should export the scene to an LS4 file which packages all scene content in to a single file. This can then be opened in Lumion v4 (does not support all features of Pro), or Lumion v4 Pro, and the videos created, or the scene continued to be updated.
B) if the architect used Lumion v4 then s/he will need to supply to you all imported models (5 models or parts of models) used, plus the scene files.
Imported Models: *.lib, *.mtt, *.inn, *.txx.
Scene files: *.spr, *.sva
Location of files: refer topic WHERE ARE MY LUMION SCENES AND IMPORTED MODELS SAVED?
in LUMION 4: Tips, Tricks and Shortcuts
The new architect needs to have access to Lumion with a suitable license, and save the files to the right locations in order for Lumion to read the files. We can provide that detail on setting things up in a separate post.
Your new architect should register with the forum for support. This will include registering the Lumion license needed to operate the application.