In the Capital Gains report if you are using Wash Sale rules then each lot is listed separately. The Wash Sale rule option is only in the Professional and Advisor versions. See "Options / Report Preferences... / Capital Gains / Use Wash Sale Rules". When this option is off the Capital Gains report lists a line item for each sell transaction, which can be from a combination of multiple purchases.
The custom report doesn't have a field for realized gain/loss, that is only available in the Capital Gains report. If you want to add the sum of Redemptions and Distributed Dividends, you can write your own user-defined field that adds these 2 built in fields. If you're in the Pro/Advisor version, there is a "Define Fields..." button on the Custom Settings dialog.