ARB design the system to work together, including the pressure switch on the compressor, I believe they can also withstand much more than 150psi. You are thinking of the air leaks in the wrong manner, its not a pressure related problem, air...
I have the factory fitted rear locker in mine, works well and has been faultless, does take a little LH and RH steering input while driving forward 5-10m to engage. Not sure how hard they are to retrofit. In the front I have a ARB (6-7 years...
Woodspoint area, not far from me, those two tracks I hadnt done in a number of years. Its a old Gold mining and logging area.
https://maps.app.goo.gl/EnSqxeUa9EbkhigT9
I would say there are numourous small internal differences, everyone here justs buys a whole H152, swaps the required parts for their engine and off they go