A question I'd like to ask first is when the items in these exchange shops will change? So far it has been the same characters.
Is there a specific date set when it will change? I don't want to try to farm towards someone like a Karin, and when I'm at ike 65/80 fragments. . boom . .shop changes and she's gone. Then, I'm stuck with 65 useless frags. Haha.

Group Shop ->
1. I'm having trouble farming these, any tips? I'm stuck at 400 right now.
2. Should I farm towards Karin or Kisame? Karin is . . . .Karin. Heals and poison all day long .. with some nice combos. Kisame, however, becomes stronger the more chakra the team has, correct? With higher combos, he could pair well with Rock Lee, whose mystery skill costs 0 chakra, thereby making Kisame stronger. . . right? I'm an Azure Fang.

Arena Shop ->
1. Should I farm towards Hidan, Kankuro, or Kurenai? Not sure who would be better. . .

Ranked Battle Shop ->
1. Should I farm towards Kakuzu? He costs 1,000 points for each set of 5 fragments. . . .sounds like a lot.

Survival Battle Shop ->
1. Tobi or continue farming Kabuto frags? Tobi costs 1,000 per 5 fragments. . . however, he seems pretty strong. . .
If I do go for Tobi, then it'll probably cut into my Kabuto fragment progress.