Will have to do some research on operating a Pentax via computer control as is standard in Astro photography. Most common is Cannon with some using Nikon. Adding IS to the exposure could produce a sharper image if it is high speed and continuous throughput the exposure. Definitely needs to be investigated.

I wonder if ibis would take out micro vibrations in long exposure (5 minute subs) in astro photography. (Motorized tracking mount vibrations).

#1 has more contrast between hair (dark) and face (light) this frames the face and emphasizes the eyes. The eyes have it.

#2 doesn't seem so dramatic, kind of snapshot generic.

Olympus waterproof. Add a small float.

Basically you are looking at 3 levels of usage to choose between for UW photography.
1. Basic snapshot, 2. Compact full control camera in case at reasonable price, 3. Interchangeable lense dslr or mirrorless camera in case (professional level).

1. The Olympus TG is a great little camera. Perfect for outdoor use, boating and light snorkeling. Drawback is the waterproofing is marginal and after many excursions into salt water it can build up enough corrosion to leak. This can be minimized by a good freshwater soak and occasional lubrication on the port covers. Olympus makes an underwater
case to put this camera in for scuba diving. Very compact good for snapshots. Overall an excellent little camera

2. Midlevel full control and excellent for diving, my recommendation would be a Cannon G7X or Sony RX-100, either in a Fantasea.com housing. Add a tray, a video light and or an Inon strobe for a complete package. Optional wideangle and close up wet lenses available.

3. Professional level; usually a metal machined housing and high end camera DSLR. Giant dome port wide angle, interchangeable ports for various lenses, twin strobes on long folding spider arms. Easy to tie up 10-25k$. Popular are the Cannon mk5 and coming on strong the Nikon D500. Usually takes an assistant divemaster to help the photographer into and out of the water with gear handling. This setup in for the really dedicated photographer, those individuals who demand the best picture quality possible. Usually a person that is deeply involved and gets great joy from capturing images. Both diving and nature. I have many customers who fit this profile.

4. Extra comments: some of the traveling dive photographers are going from the "Big Bertha" setups to a higher level compact such as the Sony 6500 level. Saves weight and space on international dive travel. Fantasea has a compact case for the Sony.

Underwater photography is challenging. Can be frustrating, but when you get it right the creatures of the Sea are amazing especially the macros.