As of 2080, has Japan changed their succession laws so that a girl could ascend the throne?
Although the issue has come up from time to time, the law has not been changed as of 2080. Once Prince Hisahito was born in 2006 the issue was dropped until after Akihito passes away, but wasn't considered a pressing issue. It was dropped again when Hisahito had children, twin boys, in 2044. The issue hasn't really come up much since.
Can you mention, if but briefly, what's happened to the Imperial Family of Japan?
Here's the list of 21st Century Japanese Emperors, as of 2080:
|125.||Akihito||1989 - 2024|
|126.||Naruhito||2024 - 2058|
|127.||Hisahito||2058 - Present|
Fumihito, Hisahito's father, never serves as Emperor - he passes away in the late 2040s. Hisahito is the Emperor as of 2080. Next in line is the (slightly) elder of the twins, Shohito, followed by the younger twin, Takahito.