Yes; the plan is for Jessica to join partway through the season for an arc of episodes after her obligations with American Idol touring are fulfilled.
Glee is going into the 4th season.
Charice appeared on Glee during season two.
Yes
yes
Yes, there will be.
If you look up Glee Wiki and type Season 4 it will tell you
There isn't going to be a season 2 on glee project
no, there is still going to be a season 3 and a season 4.
Yes there will be a fourth season of Glee. It will have all of the students who are not ready to graduate yet and even some who will be graduating this season.
Season Five of Glee aired between September 26, 2013 and May 13, 2014.
YES
I hope! Cross your fingers!