About candidates for terraforming - so far we know that High Metal Content, Water Worlds and Rocky Worlds can all be candidates for terraforming in the right circumstances. Earth-like worlds are a distinct class (it's possible that they're created when a Water World is exactly in the right place in the habitable zone.)
As far as I've been able to tell so far, to be a candidate for terraforming a planet must be naturally between around 240K and around 300K - that is to say, if the planet was in the same location and had no atmosphere, its temperature would be in that range. In practice, CFT planets will have higher temperatures because the atmosphere increases the temperature by some extent which varies depending on what it's made of. It's quite possible to see CFT worlds with stupendously thick atmospheres and stupendously high temperatures.
The habitable zones are very roughly around 1/4 AU for type M, 1/2 AU for type K, 1 AU for type G, 2 AU for type F, 4 AU for type A. It's not very exact because there is great variation between a bright star in a class and a dim star in a class. But if you jump into a system around a G star and there's a HMC planet at 1 AU distance, it's likely to be a candidate for terraforming, and definitely worth checking out.
What I usually do is check whichever planet is closest to where I expect the habitable zone to be for a star, have a look at the temperature and if it seems to be too hot, I look at the next one outwards, or if too cold the next one inwards. When I find a CFT planet I scan the ones inside and outside of it, and so on. Usually you'll get one-to-three candidates for terraforming, but in the right circumstances there can be lots. Especially if you've got a dim star or stars with planets, orbiting a big giant star at a considerable distance - that arrangement means that there's little heat from the star the planets are orbiting, and a uniform heat from the giant across all the planets, so if one is right they can all be right.
