@Blenny84 welcome to the forum.
You pose an interesting question, and IMHO, I think that there are better options than what you are looking at. Please let me elaborate. I was once in a similar situation as you. a new diver who also looked at photography as a hobby that was a huge part of my life. It was only natural that I would want to combine diving and photography. The cold hard fact, however was that by trying to learn both diving and UWP simultaneously, it took much longer before I was happy with my results in either than it would have if I had delayed the UWP and concentrated initially on mastering diving skills such as buoyancy, slowing down my breathing to reduce my air consumption and simply becoming more comfortable and aware of what is going on underwater. I honestly think that you would benefit by learning from my mistakes. Don't be in too much of a rush to start taking pics underwater. For now, concentrate on becoming a better diver.
OK, now that I am off of my "soapbox", here is why I think that there may be better options.
First, anytime that you take a camera underwater, there is the risk that you might destroy it. No matter how careful you are, underwater is a hostile environment for a camera and accidents do happen. For that reason, I would not recommend taking your only (or even your main) camera underwater. If something unforeseen does happen, then you have lost your only camera.
Secondly, both of the cameras that you are considering are "non-current models". This means that finding the correct housing for the camera may become a challenge that will only get harder with each passing day. If you are trying to save some money by going with a non-current camera, then I would shop for a housing first since that will likely be your limiting factor. (I recently bought a new but non-current camera for underwater, a Sony A6000, but not until I had ensured that housings were still available for it.)
Thirdly, looking at the camera/housing combinations that you are considering, the biggest advantage that the Fuji has is that it has interchangeable lenses. By using the Meikon housing, you might find that this advantage is somewhat limited because of what lenses will fit in the housing.
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If it were me, what would I do?
Like I said, despite the urge, I would (try to) hold off and not buy anything until I had saved enough to buy a camera and housing system that I am willing to put at risk. Use this time to hone your dive skills. In the short term, this hurts, but I think it will pay off in the long term.
While waiting, I would look for a camera with the following features (as "go-no go" requirements):
- The ability to shoot RAW. You may (or may not) shoot RAW right away, but eventually you will want to, so look for this right from the beginning.
- A camera that offers the capability to shoot in Manual Mode. Again, you may not use this at first, but eventually you almost certainly will.
- A relatively current camera with an availability of housings (ideally, housing choices).
- If you plan to travel with your camera, you will need to find the right balance between size of gear and ease of travel. This balancing act is becoming more complicated every time the airlines change their baggage limits.
- Linked very closely to the above point is finding the right balance between sensor size, resolution and flexibility (such as that gained by interchangeable lenses.) Sometimes, a high quality "Point & Shoot" will give extremely good results without the bulk and complexity of a DSLR system. You have to find what you prioritize and work with that.
If I was starting out, and it was me, and I had saved the money and was comfortable with my diving skills, I would look at something like a Sony RX100IV or RX100V. Both are current enough that there are housings available for them. (Most of those housings will allow the use of both Macro and Wide Angle "Wet Lenses" so they offer a lot of flexibility.) They can both shoot in RAW and offer Manual Mode if desired.
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WRT your question about strobes, strobes are absolutely required and both S&S and Inon make great products.
** Edited to correct a typo.
