What I would do (if I had a team):
-Build a test project that contains all your whiteroom maps.
-Each team member uses a local copy of it. (Ensures they all use the same)
- Build the game “master” project. its just built once, on a netwiork accessible location.
Now the modeller can build his meshes in his 3d application and test it in his personal version of the test project.
But instead of migrating the asset into the master project, the raw asset (fbx) is copied and imported into the master project.
the fbx (and all other assets like textures for that matter) are stored on a network folder as well.
The artist can now tweak the mesh locally all he wants.
Once he thinks the new version should go into the master project, he just overwrites the fbx on the network folder and in the master project the mesh is reimported with a single click.
The same can be done with textures.
So in a nutshell: Update and reimport the assets… Dont migrate too much