Hi Andrei,
You can do some of this at the Security Group. There is a Security Permission to Assign items, Close Items or Approve Items.
If you do not want a Security Group to Close items, then uncheck the "Allow Closing of Items" checkbox. This prevents the users in this group from seeing any status that includes the text "Close".
Same with Approving: if you do not want a group to Approve items, uncheck the "Allow approving of items" check box. This prevents the users in this group from seeing any status that includes the text "Approve".
Hope this helps!