For me, it's hard to figure out what 'would have [past participle]' means in these sentences because the meaning seems to vary in different sentences even though the forms are the same. Would it make sense if I change 'would' to 'might' or 'could'?
a) I would have thought there was nothing in that to disturb me. But I felt uneasy, and I wasn't sure why at first.
b) I'm pretty sure I caught my cold from Jason who would have picked it up at school.
c) She is a very famous comedian. You would probably have seen her in a lot of movies these days.