Q:
Two Story Journal questions
2) So to get credit during the two weeks, do I have to log in each of my six characters or just one of them?
Just one.
1) If I have an activate personal story and an active season two episode, will they both be the green stars?
Only 1 can be active at a time.
You can read about the Journal here: https://www.guildwars2.com/en/news/introducing-the-story-journal/
and listen to the Devs explain the Journal here: http://www.twitch.tv/guildwars2/profile
You can find the official answers to your questions at either/both links.
Good luck.