I have both an LRP-07 and GAP10; I put a JP silent captured buffer in my GAP10, works great and smoothed out the recoil impulse.
I still have the original non-adjustable gas block on my GAP10 so I put the heaviest spring in the JP buffer for now and the rifle has no problem locking the bolt back on the last round. It could probably use the gas cut down just a hair to soften the recoil a little more.
Regarding the gas blocks, JP gas blocks work fine but set screws and loctite for gas adjustment are a pain in the ass especially if you need to readjust as the combination of loctite plus some carbon buildup on the threads can really stick that little setscrew in place. I just changed the gas blocks on all 3 of my JP rifles from the original JP gas blocks to SLR Sentry gas blocks, much better design IMO-- 15 adjustment detents between full closed and full open, very easy to disassemble and clean, and no loctite needed. Extremely low profile & light too. I will probably change the gas block on the GAP10 over to a SLR Sentry 8, I believe the GAP10s are .875 barrel diameter at the gas port.
Regarding your approach of having the best of both worlds in one rifle by putting the JP buffer and gas block in the GAP10, my approach would be opposite-- I'd like to have GAP fit a Bartlein barrel to an LRP-07 as my preference is for the JP side charging receiver set over the Hogan/GAP receiver set.
The biggest disadvantage to the JP rifles in my experience is the .080" firing pin in their BCG which can exacerbate primer issues in non-308 calibers like .260 and 6.5CM. GAP has the edge there by fitting their non-308 builds with Armalite BCGs which use .068" firing pins.
Regardless, both are great rifles.