Is there a way to accomplish this?
The reason for this is I am trying to force spotlight to receive automatic updates when invisible files and folders are added/removed. This behavior I believe is a side effect of not indexing the meta-data (but I could be wrong). I came to this conclusion from this SO question.
Is the solution writing a mdimporter? Will it even work for invisible file types?
I'm not a Spotlight expert, but I'll take a stab anyway.
My understanding is that Spotlight will only index files of types that it knows about. If the files that you want to have indexed are of a custom type, then you will need to write a mdimporter.
I don't know if Spotlight will index invisible files.
To force spotlight to rerun, check out the mdimport command.
After some research, it seems there is no way to force indexing of invisible folders.
I am instead searching all folders and getting updates for all folders. (Still very fast if you are wondering)