iheartmods updated Frozen Lake Version 4 with a new update entry: Hotfix for 0.9 Read the rest of this update entry...
FWIW I think that the official recommendation is actually to copy all assets you depend from other content into your own map. It's a bit counter-intuitive.
Yes, that's been done long ago however, I never bothered with the dependencies because they had worked.
Where textures are mapped to. Many were mapped statically to the Dry Rock Island folder because they worked and required no effort. Now, since that map is gone, every art asset (models, textures) had to be mapped locally. This is a best practice but, speaking for other modders, if it isn't broke, we don't fix it.
Found an easter egg :] Crashed ufo in snow ))) NO SCREEN NO SPOILER!!! Some buildings are unsolid like the tower near airport and houses on lake
Replying to the second part of your message, yeah, I suck with object collisions so I make my custom assets just exist but not be solid.