Hi there, Ilana.

I can assist you on how to run a report that shows what you need.

I suggest running the Estimates by Customer report. And, customize it from there to show what is the estimate that you've already linked or added to an invoice. Please note, you're able to see this under the Estimate Status.

Here's how: 

1. Click the Reports at the left panel.
2. Go to the search icon and type the report mentioned above.
3. Select the Report period drop-down arrow and choose specific dates.
4. Click the Customize button.
5. From Rows/Columns, you can choose customer to show in the report.
6. In the Filter drop-down list, put a checkmark in the Transaction Type and Estimate Status boxes.
7. Choose Non-posting under Transaction Type to show all the data about an estimate. Select the specific estimate status that you want to show on the report.
8. Customize the other option that you wish to see in the report.
9. Hit the Run report button.

Currently, the option to show backorders will not show on the report mentioned above. However, I suggest exporting the report to an excel and customize it from there. This way, you're able to add a column for backorders.

For items that not yet invoiced and show outstanding, you can pull up Inventory Valuation Detail and customize this report. From there, you're able to see Qty on hand, asset value and, the Fifo cost. You can refer to this article to see more information on how to customize your report to show the specific data: Customize reports in QuickBooks Online.

Please check this article to see a table that contains different available reports in QuickBooks Online: Reports included in your QuickBooks Online subscription.

Don't hesitate to ask if you have other questions related to QuickBooks. I'm always here to help.