After consulting with my friend who lived in Costa Rica for some time, here's some thoughts.
1) Plenty of Photo ops (native stuff plus wildlife opportunities): yes, definitely. 2) Not absurdly crowded: yes. 3) Not ridiculously hot: depends on the location more than the time of year. Costa Rica is quite mountainous, so the elevation has a great influence on the local weather. There are two seasons, wet and dry. For more info, check out National Geographic Travel or the Lonely Planet Travel Guides. Also, take info from the Costa Rica Tourist Board, and Costa Rican individuals, with a spoonful of salt. Hope this is helpful. Pat White