And also get a good pair of strobes and some good lens?
Any suggestions on the camera or housing?
Several cans of worms here.
I've been using Nikon for UW photography since I started with a Nikonos II (which I still have) and Nikonos Vs (that I sold when I moved to SLRs)
The good thing about Nikon (and Canon I believe) is that the lenses I have are all compatible with all my cameras since the day I bought them (F3, F801, D100, D70, D300, D300s and D7100).
Nikon's new Z series mirrorless uses a different mount but you can use a convertor for the F series lenses.
It's very rare that I shoot in clear water, so I manual focus everything except when I shoot wide angle.
Strobes, plenty on the market. I have a few and some, mainly Sea & Sea.
Don't go looking for stuff with a small budget, UW photography opens a black hole in your finances, be prepared to sell your firstborn.