I've installed the hawaii-photoreal sceneries and it looks very good with FSDT PHLI. The mesh is not perfect as the airport still sits a little high. Of course, I know this is not a FSDT issue but a mesh issue. Anyway, without adding any kind of modification files to correct the mismatch, I think it is about as good as it is going to get.
I hope this is OK to post, but if anyone is interested in installing the hawaii-photoreal scenery, then here's what I did to combine the two sets of scenery together:
In the "...\Addon Manager\FsDreamTeam\PHLI\scenery" folder, I turned off this file:
PHLI_Terrain.bgl.OFF
This allows the hawaii-photoreal inland water to display as P3D water (the water mask is there) instead of the (correct color) green water.
In the "...\Lockheed Martin\Prepar3D v4\Addon Scenery\FSJ - Hawaii Photoreal Vol. 1 - Niihau, Kauai & Oahu v.0.99\scenery" folder, I turned off these files:
PHLI.bgl.off
PHLI_AG.bgl.OFF
With these adjustments, the combined scenery looks good. I hope this helps someone...