Haven't been to CDO, but I know a lot of people who have, including family, and they say it's sort of gritty and pales in comparison to Davao City. Davao City might be a little big for you, but I find it seems much, much smaller and livable than it's actual population would indicate. It's infinitely easier to get around in than say, Cebu C. or Manila. Decent airport too.
The same family has held political control over Davao City for quite a while and while they're not super crazy about Americans, (more precisely US politics) they have kept the city very safe and secure. That could conceivably change. Met a fair amount of Aussies there. There are parts of Mindanao that no non Muslim in their right mind would want to go, but it's rather clear where those areas are and Davao City doesn't have Muslim 'issues' of significance.
On the other hand, there are still pockets of communists from the top to the bottom of the Philippines and I'd guess it's probably going to be less of a problem over time, especially if the economy continues to improve. They started in Luzon and run in small pockets all the way to Mindanao, still occasionally causing problems like knocking out power lines, etc.
I'd look at Dumaguete, heard a lot of good things about it. It probably has as many college students per population as any city in the Philippines.
I wouldn't overlook Bohol, although the Japanese and Koreans are driving up the price of real estate there. Not the end all, scholarly reference, but Wikipedia states:
Unlike Luzon and the northern part of the
Visayas, Bohol is mostly unaffected by the numerous typhoons that hit the country. The weather is mostly mild all year round. When typhoons do hit the island, they usually cross quickly and are no longer powerful, their energy dissipated by the mountains in
Leyte and
Samar. Camuguin Island is just too small for my taste---all around the whole island is less than 40 miles and there's a lot of mountains all in between--I'd go stir crazy. I go crazy after a few weeks in Key West. I need things like malls, theaters, restaurants, sporting events, beaches, festivals etc., or I get bored quickly.
I don't know much about Butuan or Surigao City, except that he folks we know from there usually enjoy traveling to Davao City.
