Also, it would be nice if the output on success also stated which row updater tasks was actually executed. In my case I need and wish only to re-run the row updater for RteLinkSyntaxUpdater.

Thanks for your report. Yes, currently executing single row updaters is not possible.

A manual workarround is to manipulate the serialized string of DB:sys_registry.entry_value for DatabaseRowsUpdateWizard. Find row for DatabaseRowsUpdateWizard:
SELECT * FROM sys_registry WHERE entry_namespace = 'installUpdateRows' AND entry_key = 'rowUpdatersDone';
If all row updaters has been done, it would be:
a:3:{i:0;s:52:"TYPO3\CMS\Install\Updates\RowUpdater\L10nModeUpdater";i:1;s:53:"TYPO3\CMS\Install\Updates\RowUpdater\ImageCropUpdater";i:2;s:57:"TYPO3\CMS\Install\Updates\RowUpdater\RteLinkSyntaxUpdater";}
Just substract the single row updater, you want to run as single update and run the DatabaseRowsUpdateWizard.

Since the upgrade commands are planned to be removed in favor of the TYPO3 core upgrade commands, this feature will not be incorporated here.

Since plans change and 6.0.0 is released still with its own upgrade commands, we need to implement this