Using parameters to customize sort order + hiding columns in widgets, getting strange results

I am trying to generate an Actions widget where some columns are not shown and the result is sorted by a certain column (avg. generation time). I am trying to illustrate this using demo.piwik.org URLs.

The filter_sort_order parameter is used as expected (although it doesn’t show the visual red triangle cue to indicate the order), for example sorting by pageviews, ascending or descending.

I am not finding the parameter name to use for sorting on avg. generation time, is this possible in widgets (or in this Action widgetized report)?

I can’t seem to be able to use hideColumns consistently either, I am wondering if it can be used at all in widgets as a parameter? For example this doesn’t hide the bouncerate column, it shows the column but with empty values.

Using the same URL, I removed sorting/sort order and now wanted to remove pageviews, but the parameter has no effect.

Should I file separate bug reports for the above or am I missing something obvious? I’ll gladly stand corrected, thanks in advance for any clarification on this.