1)
The JR East English page is correct.
Yes!
BC Next Spring period sales/date official info releaced yet.
The japan-guide is correct.
No! www.japan-guide.com is
NOT Railway company's web.
That Spring date is just past recorded info.
Just until today No "sales overed/discontinue" announcement as official.
Recent some years sales/date are just fixed.
2)
Basically 18(Pass) valid only for "JR" lines
- Local (all stn stop type)
- Rapid (include "Special Rapid" in Osaka/Kyoto/Kobe area)
and special "exception" for some LtdExp in Hokkaido,Aomori and Miyazaki.
(NO in Kansai/Osaka,Kyoto and more and Hokuriku/Tsuruga regions)
So 2) and 3) both are out of exception 18 NOT covered.
Use HyperDia again by this settings.
http://www.hyperdia.com/en/https://s12.postimg.org/boquv81vx/sc0107.png
But Next MAR timetable also update yet.
3) 18? Juuhachi?
"Juuhachi" is just Japanese counting/reading both are same meaning.
http://travel-around-japan.com/blog/japanese-lesson-18-reading-of-numb...This 18 means 18 yd as age.
Seishun means "Youth".
But no age limit just like "young" means "back to/with fresh" if already an adult.
18 sales periods only in long school holidays/breaks Spring, Summer and Winter.
BC in those periods student commuter pass income will decline.
