You have confirmed ticket of Tapti Ganga which remains in high demand through out the year and as soon as its booking opens it becomes wait listed with in a moment. Right now current status in this train is REGRET/WL 718
I agree with you that different seats in different coach will be a problem for a family but you are luck enough that u got confirmed seats in this train.
Try to adjust with other passengers and request them to change the berths.
It...
more... is the only option you have.
Good Wishes.
SHUBH YATRA