I want to get some data out of the database on deleted records (EOs). Is that what the "deleted schema" is for?

You want the deleted schema all right. Each business table in Biotics has a twin in the deleted schema, which is usually called BIOTICS_DEL. You should check and see if your schema has this name. The tables are named something_DEL, so the corresponding EO table would be EO_DEL. It contains everything that the EO table has except it also has deleted_by and deletion_date columns.

To query the deleted schema, log in as the biotics_dlink user and use a query such as:
select biotics_del.eo_del.eo_id
from biotics_del.eo_del
where yada yada yada

Be sure and preface your table and column parameters with the owner of the table, BIOTICS_DEL. The BIOTICS_DLINK user has select privileges on BIOTICS_DEL. If it doesn't, you'll get an 'insufficient privileges' message. If you get this, submit a ticket to the Biotics 5 help desk with a screenshot of the error.