Advice Needed: Travel to Cebu, Siquijor, Siargao

I'm going with my family of 8 to the Philippines for two weeks. We range from ages of 4 to 76 years old. Not everyone is going to do everything but there are things we'd like to do and need advice on how to get places.

Cebu: We want to go canyoneering and Oslob whale sharks. If we stay in the Oslob area, could we also get to Apo Island and Siquijor for day trips or should we stay in Dumaguete if we want to do that?

Siquijor: What are some things to do there? Is it worth going to?

Siargao: Besides surfing, what is there to do there? One person in our party wants to go but the rest of us feel like there might not be much to do. How long should a person stay there if they don't surf?

Any must see places or things to do, or places to avoid are always welcome.