Well, any user interaction with the Qlik Sense server is trough a browser on port 443 (or 80 if you enable plain http). There's no specific port to discover Qlik Sense Servers only afaik. But you can use any port scanner to find all the servers in your network that allow connections on those ports. Are you afraid of rogue Qlik Sense Enterprise installations in your network?
QVSDetector: The QVS Detector simply scans for open UDP 14747 ports. I'd take a different approach than gwassenaar and focus on 4444 which is the heartbeat port used by Qlik Sense, especially active when adding in nodes.
QlikView Server Agent: The key functionality here is the ability to change the service account. This is not an easy process for Qlik Sense since the user account used upon first initialization is tied to the self-signed certificate used for a variety of things (e.g. data connections, UDCs). This means that you cannot simply just change it without doing quite a bit of other related tasks and is highly recommended against at this stage.