My experience with fitting HF electric lockers.

I fitted the HF E-locker today to my VVT. I didn’t have any of the issues you had with it touching the pinion gear. The only issue was removing the solenoid to get the gear ring, like you said. Then it took a while to get the backlash sorted. Just need to go out and try it out. I had an auto locker which was a bit too sensitive and would engage randomly on the road which is interesting when you have eventually got up to some speed on the roads. It’s allot better straight away and more drivable. 

I heard that the auto locker can fit the fwd diff. Might look into this as it wouldn’t matter if it engages when in 2wd 

I had no real issues with the rear diff. The problem seems to be only on the older 8 bolt front diffs.
I don't think the auto locker will be a straight fit in the front. As far as I know the later 10 bolt front diff centre is the same size as the rear but the front axles have a smaller spline.

To be honest, I don't find lockers to be as great as people make out. I can only think of a handful of cases for me where lockers were the deciding factor in getting through. Even then taking a different line or a bit of road building would have probably worked as well. The only time they really help is when you are badly cross axled. Good flexible suspension is a far better upgrade for the money.