pg_dump of table and its transitive dependencies
uses a few custom enums or other types.


No. That's because those enum types can be used in different tables and such. PostgreSQL doesn't have a dependency tracker to make this work. The only exception to this that I know is sequences, -t will recreate sequences.

That said, if you recreate the database once, you only ever have to run pg_dump -t employees -c, the -c flag will drop the table and recreate it. This will unfortunately not work with foreign key constraints pointing to employees