@pb3, this link from airwolf3d may help if you haven't already checked it out:
Compatible Dual Material Combinations

They link to their recommended ABS/HIPS settings, not sure if they match your settings above?

As for using PVA, according to the link above it's not compatible with ABS due to the higher ABS temp will melt the PVA.

Also, I talked with Airwolf a couple weeks ago and they mentioned that they are getting better results using PLA as support to ABS rather than using HIPS. Here is how they are dissolving the PLA:
https://airwolf3d.freshdesk.com/supp...a-experimental-

Hope some of this is helpful. Good luck!