Travel date moved

Good morning,
I have purchase my JRPass together with my air ticket. Also I have purchase the Pocket Wifi.
When I bought the JRP and the Pocket Wifi, the form asked me for the arrival date. I filled it, of course.
The issue is because the airline company has moved my arrival two days early.
Then, What if I active my JRPass before to the arrival date scheduled?
Also can I activated the Pocket Wifi two days early?
The second issue is because I will need two days more of train service in Tokyo that are out of JRP coverage. If I activate my JRP early, I will need two days at the end of my trip before leaving Japan. And If I wait for the scheduled date to activate the JRP, I will need two days before the schedule date for moved from the airport to tokyo and into tokyo city.
So, There is a Tokyo ticket that I can purchase for two days?

Thank you very much.
Regards,
Sebastian