Hi there and thanks.
For the video, most is filmed on a GoPro 7 Black which I always have on me (I shoot in a flat profile then wb balnce in post, and use UR Pro Cyan filters), or on the Panasonic Lumix LX10 with a Keldan SF1.5 Spectrum filter, which is my bigger camera.
Everything is shot in ambient light - the Chandelier cave sequence is on the LX10, which has a fast lens.
For post production, I use Final Cut Pro X.
Otherwise for stabilisation, the footage is quite stable to begin with - the GoPro I hold with both hands directly on the housing, which works as well as a tray when you're used to it. It's just on a coil retractor, and lives in my BC pocket.
For the LX10, I have a very heavy setup - it's a compact in a Nauticam housing and is almost -1.5kg negative underwater. I have floats compensate for that to bring it to almost to neutral buoyancy, so it's very comfy. This is good because the stabilization in 4K on the LX10 is really not good.
I further stabilize the footage in FCPX when necessary.
Regarding Palau, it's a really interesting place, and I'm sure you'll like it.
Things are still very quiet at the moment, with limited (and more expensive than usual) flight options, as you probably know. On the plus side you'll have the dive sites almost to yourself!
Famous areas are Ngemelis (Blue Corner etc) and Ulong areas, but there are also lots of walls on the outer reefs, and wrecks in the lagoon, sandy slopes and also the spawning dives, and manta cleaning / feeding areas like German Channel. Most complex current is around Peleliu.
Having worked in other places where we use current hooks, I find it interesting that the profile for the more exposed, currenty sites (Siaes and Blue Corner, for instance) are a little different from what you'd find in Indonesia (pinnacles / seamount) or Maldives (thilas), in that you're drifting along the wall before reaching an exposed hooking point, close to the exposed corner sticking out of a reef - which means you you can't really shallow up then hide in the lee side like you would on a pinnacle.
It's a little bit like a cross between a drift dive and a pinnacle dive, but with less options after hooking (usually shallowing up on the plateau, before doing your safety stop in the blue).
Hope this helps!
b