Hi Antonio,
Do you plan on living or working in Costa Rica? Because my first suggestion is to walk around there a bit and see what's growing. Costa Rica is the largest diversity of wildlife in the whole world, so I coubt you'll be lacking for resources once you're on the ground.
Native is best.
Having said that, there are some very hardy species that come to mind.
For food: cassava, carob, pigeon
pea, sweet potato,
coffee, chocolate. Looks like May through October you've got
enough precipiation to cultivate most warm-climate crops.
For medicine and timber, best get your info on the ground. But you could start with the Guanacaste tree