Is it possible to have keratoconus and amblyopia all in one eye??

Yes. These are separate conditions, which could occur in the same eye.
Keratoconus. A lazy eye can occur in keratoconus. It important that you see a specialist who can help you determine whether vision is not good due to keratoconus alone, or due to amblyopia (lazy eye) plus keratoconus.
Of course. Amblyopia comes from issues in one eye compared to the other in infancy and childhood and is a permanent change in the vision. Such an eye is not immune from getting keratoconus at a later age. So both can coexist but do not cause each other.