Upekkha: Yes to both questions.
This is why some people are able to make progress faster than others. They have “cultivated the path” more in previous lives.
However, there is an important point to remember, and that is a key difference between a “soul” in some religions and an “ever-changing self” in Buddha Dhamma.
Consider the case of a person who makes some progress on the path in a given life.
– Since he/she has made progress (even if not attained a magga phala), it is likely that he/she will be born into a family with moral values in the next life. Then that progress will continue.
– However, if one is unfortunate (due to some specific kamma) to be born into a “bad family” in the next life, that environment can stop and even reverse some of the progress made in the previous life.
Of course, if one becomes at least a Sotapanna Anugami, then one’s progress WILL NOT be reversed.
That is why we need to make our best effort in this life. Furthermore, it is essential to stay away from bad friends, associates and to associate with “moral people.”
– There is no “unchanging self.”
– One can be moral one day and become immoral due to bad associations at any time.