For Presence Updates:
No, you don't need to setup LDAP or any server side sync. The sync is all done on the end user PCs. They have to be running a 32-bit version of windows for the Outlook plugin to install.
If your all set there, then all you should have to do is run the setup wizard. You should have done that when UCA was originally installed, but if you missed it or want to run it again, no problem. You can run it again by going to the Mitel symbol in the upper left corner, and choosing "Run Setup Wizard."
If you good on both of these, then you need go into the client configuration, and the Calendar Integration section. Make sure that the check-box for Enable Outlook Calendar Integration is checked.