what you can do using the API is the same that you can do using the Softlayer's control portal, You can see all the permission that you can grant to the users by going to:
- Account->Users on menu
- Click over an created user and click on permissions

There is a permission to allow to your users see the billing items, this permission is called "View Account Summary" so you can disable the permission and your usaer will not be able to see the invoices. For servers there is a permission called "Add server", but this permission is for Bare metal servers, Virtual guests and for the rest of oders if you disable this permission your user will not able to order neither Bare metal servers nor Virtual guest.

Now using the API you just need to use the method:
http://sldn.softlayer.com/reference/services/SoftLayer_User_Customer/addPortalPermission
e.g. using REST:
POST https://$USER:[email protected]/rest/v3/SoftLayer_User_Customer/$USERIDOFUSERTOEDITPERMISSION/addPortalPermission
payload:
{ "parameters": [
{
'keyName': 'TICKET_ADD'
}
]}
You can use this method to get the list of all permissions in softlayer:
https://sldn.softlayer.com/reference/services/SoftLayer_User_Customer_CustomerPermission_Permission/getAllObjects
Regards