ORA-39083: Object type INDEX_STATISTICS failed to create with error
Excluding statistics is safe in the sense that it doesn't affect the actual data you're importing. You can always recalculate the statistics in the restored database.

If you need that restore to do performance debugging on specific queries, that's going to be a problem - you'd want to have exactly the same statistics as for the source database for your tests to be realistic. (But you can always re-export and import the statistics specifically if you need that.)

That being said, nothing's really "safe" with a corrupt database, and that type of error "shouldn't happen". It's possible I guess that the export you're running on failed partially. Check the export log file for errors too.