Before anything else, I would like to point out that finding any future content info about this, is very very hard, and even after doing hours of digging things I found are nowhere near a full list, more like a few highlighted points.

What is more every single server get's things in scrambled order, so it is impossible to tell WHEN we will get what. Examples : Germany gets Jinjuriki 2 treasure 2 weeks after 3.0 update, we got it one week before. Chinese server gets Kurenai, neji, kiba, shino ninjas in home 2+ months after 3.0 update. We got them as it was released. (Please do keep in mind that it also does not mean we always get thing earlier)

Anyhow, let's get to it, what can we expect of early 3.0 to bring to the table?

1) Kushina draws near :

Mystery : Causes High float and interrupt. Can be cast on teammate to remove debuffs instead.
Standard attack : If there are no clones, summons 1 - 2 clones.
Chase : Chases repulse causes knockdown immobile.
Passive 1 : If there are clones on the field, attacks 1 target causes repulse
Passive 2 : Heals self before action.

On this server she was obtainable in Sage chest event, costing 18 points per fragment. In comparison Jonin Minato costed 50, Edo Sasori 40.

And on that let's move to next ninja likely to appear in next couple of months :
2) Edo Sasori

Mystery : Grants additional attack up to 9 Edo Tensei ninjas from your field, and removes one layer of debuffs.
Standard : Causes damage and poisoning
Passive 1 : If there is a dead ally, may cause chaos to 1 enemy unit.
Passive 2 : Generates shield 40% resistance up to 9 Edo Tensei, increases damage 30%, last 3 turn
Passive 3 : If killed will resurrect with 30% hp after 3 turns.

(Thank you for correcting translation mistakes for Sasori, I knew I wouldn't have to wait long :P)

3) Orochimaru Konoha traitor Skill Break

4) This the most likely next costume we'll get :

5) And since we are at it already the next one too :


6) Kabuto Skill Break
Also with that Skill break get ready for Kabuto to be monthly login ninja, it is what happened on source server. Skill books in x days attendance.

7) Ultimate training more stages :
Pretty straight forward here, and yes Tendo fragments come with this too, however I would not expect this to appear until the next treasure is near to arrive, since it does use ninjas from this treasure.

8) Gaara Skill Break :

Disappointed in monthly Kabuto fragments? Don't worry, next month source server got Gaara as monthly :) Skill books included too.

(Post still being written, I'm tired though so will take a few hours of rest)