I mean drush and db credentials from external sources. Looks like OP has no clue how
php.ini files works within CLI environment. He even posted snippet showing drush is using other
php.ini than the one he defined his parameters in. On the other hand smart use of drushrc and
ini_set() could do it. But again, he knows about drushrc, knows about
ini_get(), and yet he looks like he failed to see "See also" block on
ini_get() php.net page and notice
For me it's between Questions that lack any research effort, too broad and unclear (due to lack of info why credentials ended up in php.ini in the first place). Not quite far enough either way for me to vote, but not really good none the less.