Hi,
1. Yes your system is EHP7 for SAP ERP 6.0 when you see the SAP_APPL and EA-APPL is at 617. Other software components would be at 600 patch 91 (SAP_HR, EA-HR, IS-CWM, IS-H, and IS-OIL).
2. Yes, use MOPZ to generate a stack file along with the product IS-RETAIL which will automatically add necessary other components and required patches to your stack file. Basically as like other upgrades MOPZ will take care of other dependents.
3. Later use SUM to apply these add-ons and patches.
regards
kartik