You don't need to enable all extensions... like @AndyB did above, you just enable the ones that your existing version is already running. There is no point having databases or such active that you don't actually use, or other features.
For those using cpanel, you can run php_fpm by ensuring that your sites are assigned the php version and not inherit it, within the multi-php manager. Even though you may only have php version installed, php_fpm requires strict assignment before you can enable it for a domain. Its worth it.
Why do you want them enabled? My limited understanding is that these are the common exploits people attempt, especially known in Wordpress installs. Disabling those php functions is usually a good thing.