Yes, those changes are grammatically valid, and will make no significant differences in meaning.
More specifically all of:
- Life has changed a lot in the last thirty years.
- Life has changed a lot over the last thirty years.
- Life has changed a lot in the past thirty years.
- Life has changed a lot over the past thirty years.
are valid, natural, and mean essentially the same thing.
The use of "past" perhaps stresses the past a bit more, but that is debatable. The use of "over" suggests a process of change more, while "in" suggests more of a then vs now comparison, but these are very fine nuances, than many may not even notice. Some might even disagree with these nuances of meaning.
The sentences may be treated as interchangeable.