Would disabling these following functions in PHP.INI affect Drupal 7?
Yes, that may cause odd debug issues down the track.

Some of those are required by drush:

i.e:


escapeshellarg
escapeshellcmd


symlink is used in system.tar.inc

Modules such as devel and advanced_help use parse_ini_file

Other contrib may use others, e.g print_pdf uses proc_open