components/com_comprofiler/plugin/user/plug_cbgroupjive/templates/default/template.css

Yes this is the correct path.

Can you tell me where are the lines on the following fields because no code says ?

It doesn't exist, there's no specific CSS; it's all generalized in an API standard. Meaning the CSS used all throught GJ preventing duplicate styling. You need to add new CSS targeting those specific fields. Using Firebug you could inspect the page revealing their classes, ids, etc.. to hide them. Best approach is to remove them entirely from the PHP file group_edit.php otherwise someone could remove the CSS at any time and edit the inputs as they see fit.

OK But if I remove them from the groupe_edit.php do default values ​​of these fields will be preserved?

Yes, PHP validation is designed to set defaults. This assumes you are not removing any fields labelled as "Required".

I ask many questions can be, because I'm not a developer.

It's all about trial and error, simply make a backup, edit the file, test and see if it's to your liking.

Please do not post GJ source, it is only available to subscribers and not meant to be made public.

I can not tell you if your changes are future proof; they will be lost on upgrade of course and you'll need to re-add the changes each upgrade or provide your own template, which can override files (copy-paste default template in template folder; delete all but for group_edit.php in this copied folder then select your template from backend).