I've updated the Freighter guide, as the 33% hull resists make huge difference in their lives. However the armor tanked Providence is still better than the triple-bulkhead Obelisk. The Obelisk has 5% more EHP, but the Providence has 40% more cargo, benefit greatly from link ships and easier to repair. The Ark stays the best in all fields.
For Orcas, it is worth considering getting a faction Damage Control.