We would like to add a new column “Last block Produced” to the witnesses listing page which would display for every witness the last block number they produced.
Is it possible to expand the endpoint to include, for instance, last_confirmed_block_num (this task), and potentially others such as account_creation_fee ?
Alternatively, we could call condenser API but the extra call wouldn't be optimal.
Yes, we can enhance the output to include such data. You're right, it would be a step backward to use condenser API as we're trying to remove most such calls eventually from API nodes (at least the ones that are actually calls to hived). You can create an issue in hive/haf_block_explorer issues to get this data added to the API call. Just FYI, we're currently working heavily on the hafbe api, so it's a good time to get such requests in.
The backend task (haf_block_explorer#77 (closed)) is completed. We still need to spin up a new API node with the new feature. We have a few more bug fixes/improvements coming in balance_tracker (balance_tracker#22 (closed) bug fixes for coin history calls and balance_tracker#21 additional coin balance types), so we will wait to those are also done before we spin up the new api.syncad.com, but I guess it won't be too long.