Sync Agent is controllable through the Cisco Unified Servicibility interface on the IM&P servers.
Yes, you need DNS. The _cisco-uds SRV record will point Jabber clients to CUCM. Without it, you would need to manually configure the Jabber client to point at the correct server - a really bad idea should you ever want to change the hostname or IP of the server.
Jabber is more involved to setup than CIPC was because you need to configure a contact/directory source (eg UDS vs. CDI), likely application and directory lookup rules, service profiles, a jabber-config.xml file, and various ancilllary features depending on requirements such as managed file transfer. If you’re doing this alone without a partner engineer who [should have] done this before it will probably take you a week (or two if you also needed MRA) of reading and testing to get it fully setup.
