I think this piece is quite lovely. It appears that your couch and chairs have dark wood so I would be tempted to stain or paint the buffet to match these items. Changing the large modern handles to smaller antique ones might help to make it less bulky looking and tie in with the other items in your room.. I like the idea of putting a mirror in the upper door, however much as I like the criss cross effect in the sample pictures, adding more detail may conflict with the curves in your sofa and chairs. You could look for a decorative detail that has more subtle style. As for placement, it might go on the short wall where you have a bench or even on the wall where you have your table with two chairs, one on each side to balance the look.

I would say definitely teak for outdoors in the tropical climate. Wicker would be fine if it's in a covered area. Here is an article about different woods for tropical climates. "The price of sustainably grown tropical outdoor furniture is becoming more and more affordable as the industry utilizes other varieties of sustainably grown tropical hardwoods, such as the following: Eucalyptus is a sustainably harvested plantation grown hardwood that possesses a smooth finish, lovely grain and a rich honey-red color that weathers beautifully due to the high oil content of its wood, and it smells good to boot. If allowed to weather naturally, the wood will take on a pleasing soft gray patina. It can be stained to retain the rich golden red color of the wood, however most people prefer the soft gray patina. Eucalyptus is less expensive and much easier to maintain than some of the other woods used for outdoor furniture. Balau is also one of the hardest of all tropical hardwoods. It is much more dense than teak and is in abundant supply. Like eucalyptus, it is more affordable than teak and will also withstand years and years of exposure to the elements. You will want to treat the wood occasionally with good wood oil if you wish to preserve the natural color, however this is a very low maintenance outdoor wood. Teak for good reason has become one of the most sought after of all the tropical hardwoods. Although it was at one time the preferred hardwood, along with mahogany, for ship building and decking, it is now grown on teak plantations due to its scarcity. The demand for teak is still high among those who are able to make the investment in furniture made from this beautiful top quality wood. Teak outdoor furniture is one of the more expensive options for outdoor furniture." http://www.thehouseandhomemagazine.com/Articles/Vol1No8/OutdoorFurniture/tabid/228/Default.aspx

A combination of Offwhite, Beige Upholstery and dark shades of wood would look good. Provided you keep the wood minimal . The floor can also be a similar shade of wood . Remember whatever you do, make it look rich and elegant, only then will you be able to pull this look off. I am assuming the your ceiling is considerably high as well. Paint the walls and ceiling in offwhite shades with only the feature wall grey

What kind of outdoor furniture you are looking for and pls mention budget as well .