To change the defaults in the web site section you need to edit

/usr/local/ispconfig/interface/web/sites/form/web_domain.tform.php

find and replace

'default' => 'webalizer', 

with 

'default' => 'awstats', 

do the same with

'default' => 'fast-cgi', 

to

'default' => 'php-fpm',

 

 

 

DP