Create custom language file below. The language data in qa-include/lang is overwritten by language data in the custom folder.
qa-lang/custom/qa-lang-main.php
<?php
return array(
'date_day_min_digits' => 1, // 1 or 2
//'date_format_other_years' => '^month ^day, ^year',
'date_format_other_years' => '^day ^month, ^year',
//'date_format_this_year' => '^month ^day',
'date_format_this_year' => '^day ^month',
'date_month_1' => 'Jan',
'date_month_2' => 'Feb',
'date_month_3' => 'Mar',
'date_month_4' => 'Apr',
'date_month_5' => 'May',
'date_month_6' => 'Jun',
'date_month_7' => 'Jul',
'date_month_8' => 'Aug',
'date_month_9' => 'Sep',
'date_month_10' => 'Oct',
'date_month_11' => 'Nov',
'date_month_12' => 'Dec',
'date_year_digits' => 4, // 2 or 4
);
However, I think that there are programs directly using PHP time formatting functions, so all of date formats may not be changed by this.