All non-required fields can be removed as you see fit, but I don't recommended it as it allows customization of the group to the individual. At any rate to remove them you need to edit the template file found within GJ template folder. Location as follows. If you're meaning "Category" and "Owner" parameters then only Moderators can change them.

components/com_comprofiler/plugin/user/plug_cbgroupjive/templates/default/group_edit.php

3 of the selected fields are Required, meaning you can not remove them as attempting to save a group without them will result in validation errors. As for the others you simply find them in the location I've already provided and comment them out (with //). Integrations is a single field however and disabling it will hide ALL integration parameters (Wall, Forums, etc...).

Another question, how do I change the explanations of English in French in the icon i. Could you tell me which file I can find them?.

GJ comes with an English language plugin. Simply install and translate as necessary. Language is translated from same location any string in CB is translated from (language folder). See CB documentation regarding language file location.

Is this possible?

Yes, you have to edit the template as instructed earlier and remove them. Alternatively you could just use CSS and set their display to hidden (they'll still show in the websites source though). Again however, you can not remove Required fields. Doing so will prevent the group from ever saving due to validation errors.