Ipe is very nice stuff. Super hard and heavy. A naturally oiled wood like teak. Very expensive. An excellent choice.
I wouldn't do cedar because it's so soft. Pure heart wood would be harder, but the cost is not worth it.
The newer plastics that are out are nice. They won't warp, are mold and mildew resistant. They also cost more than green treated. Products like Trex can be bent into complex curves. Of course the properties that allow them to be bent also means the product is rather weak. Pick up a 16' 2x6 and the ends will touch the ground. Your span rating with Trex is limited to 16". Something to consider.
I presume that you are not going to pull the pier unless ordered to. For your structure you'll want to use MARINE treated pilings. So long as you don't want to tie the Formula up to it, you'd want to use 4" posts. This is something the local lumber yard will have to order. The regular green treated ground contact wood that is in stock won't last in a marine enviroment. Sharpen the post with a hatchet and make up a pile cap that you can beat on. A piece of pipe with a 1/4" plate welded to the end works well. Now get out there in your row boat and start beating on it! Take marine pressure treated 2x4's and put one on each side of the pile so they cross and form a X. This will brace the piles against the boat. Try to keep the angles at a 45. The one end will be below the water line. At the end of the pier, turn the bracing so it runs parallel to the pier. Now put 2x8 standard treated headers (horizontal) for the deck to rest on. If you want to use a plastic decking you will need to run some joists (stringers). The material will proably require 16" spacing. This will give you 3 stingers for a 4' wide pier. If you go with a 2x8 you can span around 8'. Get some Simpson LUS26 hangers and face SCREW them to the headers. Drop in the joists and the pier is now ready for for your choice of deck.
Usually we just set the piles at a 5 foot spacing and then laid 2x12 planks across a 2x4 header.