rekordbox doesn't recognize DDJ-RZ as an Audio source/

I'm glad you figured it out through some very intensive exploration, but this guide to your issue is linked on the same page from which you downloaded the drivers:

0) Have you read the "READ ME FIRST" thread in its entirety AND TRIED THE SOLUTIONS THERE before posting:  Yes, I swear it!
1) Operating System: OS X 10.14.2
2) OS Type: 64bit / 32bit
3) rekordbox version: 

A follow up post reading the "Read this article before posting"

4) Using LINK: No 
4b) LINK Connection method: N/A
4c) Using with CDJs: No 
5) Source Hard drive / Flash drive / SD card file system: HD/Desktop
5b) Connection type: USB3.0 to Thunderbolt 
5c) Does the device have multiple partitions: No 
5d) If it's a flash drive, is it a U3 device: N/A
5e) With what utility did you format the device: N/A
6) Export Hard drive / Flash drive / SD card file system: N/A
6b) Connection type: USB3.0 to Thunderbolt
6c) Does the device have multiple partitions: N/A
6d) If it's a flash drive, is it a U3 device: No Yes Unsure
6e) With what utility did you format the device: N/A
7) Have you scanned your files for errors: No 
7b) Have you scanned your drive for errors: No 
8) Is rekordbox crashing at all: No / Yes
8a) If crashing, is it resulting in: N/A
8b) If not crashing, are there any error messages: No 
9) Are you able to repeat / reproduce the problem: Yes -by uninstalling and reinstalling
9a) If yes, can you do it consistently: Yes
10) Does the problem occur with one specific song: N/A
10a) If yes, please post a link to it: N/A
11) Any other notes regarding your setup only:
12) Provide as much detail of the issue here

Thanks

Hello Support,

I would like to include the USB 'Software -Extension' info below.

Hope someone can help me resolve. I've been at this for hours : (

Hello Support,

For those experiencing similar issues.  I determined that Mac Mojave, Kernel extension manager - for lack of a better term - rejected the "driver" illustrated above.

After some sweat and tears : ) I found a workaround, as a permanent solution is yet to be determined.

1. Located the Drivers Bundle ID
2. From your terminal enter-

$ sudo kextutil -b <Bundle ID>

1. At this point you'll get an error similar to this:

Kext rejected due to system policy: <OSKext 0x7fd87271f950 [0x7fff836b48f0]> { URL = "file:///Library/StagedExtensions/Library/Extensions/DDJ-RZ%20USBAudio.kext/", ID = "jp.co.pioneer.driver.DDJ-RZAudio" }

Diagnostics for /Library/StagedExtensions/Library/Extensions/DDJ-RZ USBAudio.kext:

Warnings:

    Dependency lacks appropriate value for OSBundleRequired and may not be available during early boot:

        com.apple.kec.Libm - OSBundleRequired not set

        com.apple.vecLib.kext - OSBundleRequired not set

        com.apple.iokit.IOAudioFamily - OSBundleRequired not set

1. Go to Systems Preferences >> Security & Privacy
2. You should see a "Software was blocked..." message similar to below.

1. Click on Allow.

You should now see the Audio of your Controller populated like so.

I hope this helps.

Thanks