Regarding the hotness of the output from AD2, I find if you use the AD2 track template (or something similar) you can pull down the input gain of the midi track and it lowers the gain on all the drum tracks. (Please correct me if this does something else that is bad :P )

Also, with the new update to AD2 you can now output from AD2 Post-Fader. I haven't tried this yet but I assume that would work too.

- I've found that if any other audio track is also sending to the parallel bus along with AD, then there's no problem. This can be a track with a recorded or bounced drum part, another soft synth output or even an audio track that just has input echo enabled with no signal on it.

 
This workaround solves the issue for me too.
 

- The phase error seems always to be exactly 64 samples, so in lieu of adding some other audio track sending to the parallel bus, the phase error can be compensated by adding a 64-sample delay to the parallel bus using Channel Tools or some other sample-delay plugin.

 
I had no luck with this using Channel Tools. In my case it wasn't 64 samples that fixed the phasing. I didn't have time to fiddle around to find the exact number of samples, just thought I'd quickly throw in 64 as per your solution and see what happened. It did change the sound of the phasing though!   
 
Thanks for the heads up on this, I thought I was going nuts when I heard this!

millzy
In my case it wasn't 64 samples that fixed the phasing.

That's odd because another user in the other thread reported that Addictive Keys also requires 64 samples of PDC for its onboard FX. This really shouldn't vary from one environment to another.
 
Glad to help in any case.