We monitor a lot of our security tools using the Zabbix platform. I've installed the Zabbix Agent on our DXL brokers/TIE servers with good success.
Are third party agents supported?
Strictly speaking? Probably not. However, we've had a number of issues I've had to engage with McAfee support on, and I've not had any issues receiving support due to the presence of the Zabbix agent. In fact, in one case we worked with McAfee support and used the Zabbix agent for JMX monitoring of the tieserver process.
From what I've seen the TIE/DXL systems are based on RHEL, so any RHEL rpm you find should work on those systems.