Thank you for the information OP! Searched high and low for a working bluetooth audio setup after getting this car. However, I do want to throw my 2 cents in on what worked for me.
2008 Infiniti G35X w/ Technology, Premium, & Navigation
Acquired used so it didn't come with the cable. Purchased the OEM Infiniti cable 284H2-1BA0B from Circle Infiniti on eBay for $35 shipped, the WMA1000 for $89 on Amazon, and the Cablejive DockStubz+ adapter for $22 from Amazon. I already had a 12V to USB adapter handy.
Now when I plugged everything in and turned on the car I was able to connect right up to the WMA1000 via bluetooth and everything worked great. However, it did not want to reconnect once I shut off the car and turned it back on. I noticed my USB adapter was flickering & making a ticking sound (evident of a failing power supply), and the WMA1000 was not powering on. So I unplugged and replugged in the USB cable and it started working. I then tried without the USB cable plugged in, and it worked great! Power off, the WMA1000 would power off, power back on and the WMA1000 came back on and was connected to my phone and auto playing Spotify within seconds. So I thought, what if I don't even need the Cablejive adapter. I figured I would at least need it for the 30 pin charge conversion. HOWEVER, once I just plugged the WMA1000 into the OEM harness, it came on and worked. Did my on/off test, and once again it powered up with the car, connected within 5 seconds, and was autoplaying from Spotify again. So for my setup, all I needed was the WMA1000 and the OEM harness.
Now, I think part of my success was spending extra for the original Infiniti OEM harness and not the cheaper aftermarket solutions. That's the only thing I can figure.
I am going to continue testing for a few days, and if all works without problems I am going to return the Cablejive adapter ($22 is $22 after all).
And for those wondering since I couldn't find it ANYWHERE else, Spotify DOES display the artist and track information on the screen and you CAN use the steering wheel controls to skip forward and backward. Loving this thing!
EDIT: Forgot to mention I'm using an iPhone 6s Plus with latest 9.2.1 update, and my final config is OEM Infiniti harness to WMA1000, no additional adapters necessary. I have a few songs in my library, and they show up and play just fine with artist and track info (no album cover art). However, I mostly use Spotify for streaming, and it works great, along with navigation via Google Maps (the $150 plus dealer fees to update navigation on this thing is HILARIOUS!) and the phone side connects with the built-in bluetooth and makes phone calls just fine. Music fades out and resumes during phone calls fine. Another side note, though the 6s Plus is not listed on Infiniti's bluetooth compatibility list, it does work as you'd expect, but you can not download the phonebook entries. You can only make and receive basic phone calls. Which means you have to use your phone to initiate any phone calls (if you don't take the time to manually edit every entry in the phonebook...which who is gonna do that), though you are able to receive phone calls just fine. So basically the built-in bluetooth is only good for making phone calls that you initiate on the phone itself or receiving incoming calls. Total bummer for such a nice bluetooth phone & navigation system that is borderline unusable.
However considering the time frame this car was built and what was available then vs now (technology changes so fast!) you really can't complain all too much.