It sounds like you have a great start on the decorations--you can add some big cardstock "flip-flops" to hang up...trace out the shape, cut, and glue wide colorful ribbons on for the thong>>add a big flower (can use fake flower or even a tissue paper one).
Since the Hawaiian tropical feeling is all about bright colors, flowers, fruits, grass, bamboo...adding things like a grass skirt in front of the food table sets it off...or using bamboo mats under food platters.
Make some brightly colored tissue paper flowers on pipe cleaner stems.Here's how with a video (you don't have to buy garden stakes...use wooden skewers for the stick)>>
If you're not having leis for the guests to wear...why not make them each a barrette with a flower and ribbons? can be a take-home souvenir gift.
Oftentimes tables are decorated with fruit (pineapples, mangoes, bananas, macadamia nuts, lemons & limes and coconuts)...any food items containing these items are good tropical food choices.
Here's a good main dish: TERIYAKI PINEAPPLE CHICKEN (I would decrease the teriyaki amount to 1/2 cup, omit the red pepper flakes, and maybe add 1 tsp of sugar if you want it a bit sweeter). You will have to double this recipe for your crowd:
You can serve this in pita pockets to eat in a casual way.
Make any kind of a salad you want....fruit and brownie kabobs in an easy fondue are fun>>
Make some brownies, cool completely, then put into freezer for 20 minutes (so they won't crumble when cutting!)---then cut very small bite-size pieces and alternate on party picks (brownie, green grape, brownie bite, slice of strawberry). To make an easy CHOCOLATE DIP FONDUE>>get a can of Pillsbury frosting, empty it into microwavable bowl, (high for 20 seconds), stir and use for dipping...can make it mocha flavor using 2 tsp of instant coffee mixed with 1 tsp water...mix those thoroughly and THEN add to the frosting to heat up.
Music: reggae, Jimmy Buffet songs
Games....coconut bowling? make pins from 2 liter bottles with caps ..fill bottoms with sand or kitty litter to weight down.
Pass the marshmallow: give each person a straw...first person sucks the marshmallow to the straw and holds it to pass to next person who has to suck it to their own straw and so on. First team done, wins. (have 2 teams)
Hula hoop contests...who can do it the longest. Have a timer
M&M Scavenger hunt>>this is easy...colors are worth points, but guests don't know which is which:
Tourist Relay Race>> Fill two beach bags each with a grass skirt, sunglasses, lei necklace, straw hat and tropical shirt. Divide players into two even teams and have each team line up at the starting line. Place two beach chairs about 20 feet away from the starting line. Put a cooler with small, kid-size fruit drinks in between the chairs. On "go," the first player in each team has to put on everything in the beach bag, run and sit down in the beach chair, drink a kid-size drink from the cooler and run back to the starting line. She takes off the beach attire and the next player in each line does the same. The team who has all their players complete this first wins the game.
your not gonna get far $50 sweetie