How to sync my iTunes library to my iPhone while still using iCloud Music Library for Apple Music?
Ok, I think there is a way to do this, but it is not my preferred method.

When you have iCloud Music Library turned on for your iPhone or iOS device, you will also need to make sure it is turned on for your iTunes library on the desktop. When you do so Apple automatically uploads your iTunes library to iCloud. Then, your iTunes library shows up on your iOS device. If you want to save those tracks locally, you must choose to do so within Apple Music on the device itself.

Basically, Apple has done away with the idea of syncing your music locally through a USB cable, you must do it over the air via your data connection or WiFi. Kind of stupid that it has to go through Apple's iCloud servers first and then back to your device...