Yes.

There are two different kinds of chlorophyll that are found in leaves: chlorophyll a (which is medium green) and chlorophyll b (yellow-green). The more light is absorbed by a leaf (and so the darker it is), the more chlorophyll and other pigments (like beta carotene) there are inside.

Yes - leaves have different amounts of chlorophyll. There are ginko leaves near me that are green by the stem, where they still have lots of chlorophyll, and yellow out at the edges, where most of the chlorophyll is gone. Some leaves have white on them, and there is [almost] no chlorophyll in the white part. There are also molecules with colors different from green chlorophyll in many leaves, and they make the leaves show different colors. I have plants that had leaves so dark, they were almost black, when I got them; but now I've watered them and their leaves have lots of green in them, and they're much bigger, and they're red-black now mostly just at the edges and ends of the leaves.

Different kinds of leaves do contain different amounts of chlorophyll. Variation has been found across several groupings plant/leaf types. For example, chlorophyll content is larger in the leaves of trees than in those of shrubs, which in turn have more than herbs. In addition, the "leaves" of evergreens contain more than those of deciduous trees. There is also variation within a single type of plant/leaf (e.g., looking only at the leaves of trees). Some of the factors influencing chlorophyll content are temperature, water (e.g. rainfall), light, and environmental stresses on the plant. Plants which receive appropriate amounts of these are generally healthier and have more chlorophyll. Interestingly, latitude and soil conditions were found to have relatively little effect.

Yes! In fact, it is different amounts of chlorophyll that causes leaves to have different colors. You probably already know that chlorophyll is green. But, there are lots of chemicals that are different colors in leaves! For example carotenoids are orange, xanthophyll are yellow, and anthocyanins are red. The different amounts of all of these chemicals changes the color of the leaf.

So a leaf that is very green probably has more chlorophyll compared to the other chemicals. In the fall, some leaves turn red or yellow. This is because they have less chlorophyll compared to the other chemicals.