Marking an item as private is controlled by the "discoverable" boolean column in the item table in the database. Can you please verify that the values of that column are not False or f?
The solr indexing issue seems to be caused by empty aat/contributor fields in some of your items. See here: https://github.com/DSpace/DSpace/blob/master/dspace-api/src/main/java/org/dspace/browse/SolrBrowseCreateDAO.java#L160
As for the last error, could you please verify that the ORA-00942 table exists?