Can I see the total estimated value of all auction items?

Yes! Here is how to get the total value of all auction items

From your dashboard, click auctions > manage > bids, which will show you a table of the items. You can select to display the estimated value from the book icon drop-down menu. You can then click the arrow icon to download this table as a CSV file, and use excel or Google sheets to "sum" the estimated value column.