Climbing Mt Fuji

How do we refill the water at Station 8 & at Summit?

By buying water bottles at the shops or vending machines along the way. Prices increase with altitude.

Thank you Uji.
Do they have lockers at Station 5?
How to get to Fujinomiya Station from Taisekiji?
Station 5 & 8 & Summit, do they include 2 meals? Breakfast & dinner? What if I want to buy extra food for lunch?
What do they provide at the huts? Do they provide sleep bag or blanket keep warm?
I have 3 extra days in Japan, where can I go visit? between Mt Fuji & Tokyo, any good suggestions?

Do they have lockers at Station 5?

There are lockers at the Kawaguchiko 5th Station, but I am not sure about Fujinomiya 5th Station.

How to get to Fujinomiya Station from Taisekiji?

During the climbing season, there are buses from Fujinomiya Station to Fujinomiya 5th Station.

do they include 2 meals? Breakfast & dinner?

Yes, I believe that most huts offer two meals. Or at least an option to have two meals. Most huts also have other food on sale, which you can use as a lunch.

What do they provide at the huts? Do they provide sleep bag or blanket keep warm?

Blankets are provided. During busy nights, you sleep head on foot.

I have 3 extra days in Japan, where can I go visit? between Mt Fuji & Tokyo, any good suggestions?

I recommend to make a selection based on interest:
http://www.japan-guide.com/list/e1103.html
http://www.japan-guide.com/list/e1104.html