chins and dips are both good bodyweight cals. now im no expert but this is what i know. chins do biceps and lats (mostly). dips do delts, triceps and pecs. hope it helps.
yeah, you are right. dips, kind of depends what dip you use, chest dip has a focus on chest and i think it works the shoulder more also than the triceps dip which is mostly about the triceps.
chinups takes the back, upper i think and mostly the lats and it also works the biceps pretty good
If using a dip station the wider your grip the more chest you incorporate. A narrower grip is going to hit the tri's harder. Either way it is a good tricep workout and chin ups are going to work your bi's more than any other muscle.