[Jiri Fiala] “I wanted to retain as much easy re-connectability from the original tree folders (stored in the broadcast facility) as possible,”
You cannot reconnect to already-imported tree-format media since the only allowed import is via copy within library or other designated location specified by the FCPX library inspector>Storage Location>Modify Settings>Media.
During the import FCPX will reorganize and often rename the files to a sparse group of folders. To handle filename collisions it will append (fcp1), etc. to some files. After that, any link to the original tree-format media tree is gone — the data has been restructured by FCPX during the ingest.
Once the “copy”-style import is done, the files should be within the library or designated storage location. If you abort the copy (which is easy to do — just moving the cursor may pause it, as shown in the above video), then all media has not been imported, but is split between the partial content in the library and the import source.
In that case the solution NOT to consolidate, but as shown in the above video: re-connect the media source, select the red/black clips or those with a camera icon on them, then do File>Import>Reimport from Camera/Archive.
People frequently encounter problems with this area. IMO it’s best to bypass these issues by re-wrapping tree-format media with EditReady2 and import with “leave files in place”. It is faster, less confusing, maintains a small “lean” library, and gives you (not FCPX) control over your media folder structure and filenames.
Also do not copy the bare video files out of the media tree and import those. In some cases like Sony XAVC-S you can get away with it. In other cases like AVCHD it will cause major I/O performance problems.