Notice this one was posted about a month ago.
In case you haven't worked it out, and to help others...
1. No, these will be two separate connections, so the directory connector will import from both. To remove the users in one go, delete the connection, and you will be given the option to remove all users imported from that connection.
2. Yes you can.
Have a look at the following video tutorial which explains how.. Qlik Sense Platform - Qlik Management Console User Directory Connector - Part 5