Well at this point it appears that whatever you do should be as beautiful as the tile job.
I do a lot of work with wood so I’ll punch in my 2 cents worth…
1) Poplar is a good material simply because it is strong and dent resistant. Downside is that it takes stain very poorly so you’d have to condition all the components first prior to applying stain. Also depending on the variety the grain of the wood can have a lot of green that also ends up looking strange with coloured stains.
2) Maple is an idea material for any cabinet/furniture. It is super strong and resilient and takes stains beautifully. Only down side would be cost.
3) Oak is always a beautiful material for finished furniture and would give your table a very traditional feel. Again only downside would be cost.
4) Cherry this would give you a truly unique finish. Cherry would give durability and be one of the most visually dramatic finishes.
There are a huge variety of exotic hardwood also available if cost is of no concern, some of which would make this truly a one in the world type piece (not that it already isn’t).
Curious, and maybe I’m just missing something, but how are you going to handle the sea zone divisions? Are each of the tiles meant to be a sea zone? I guess I need to go back and take a closer look.
Unbelievable work. You must have the patience of Jobe.