Hello Aspirant,

Character Certificate is a document which tells about a candidate that he/she is of a good moral character. You can obtain Character certificate from institution in which you have last studied or from police. However, Since you already have character certificate from your last institute where you studied, you can attach the same in your university form. You'll not face any problem. Still if the university doesn't accept it, you can fill an undertaking and apply online for an PCC.

Good Luck

Hii!
You haven't mentioned the name of the University and the course you are taking about. And, you don't need to worry about this problem. Allmost all universities accept the class 12th certificates as long as you satisfy the eligibility criteria for the respective course. So, being a dropper and having a certificate from 2016 should not be a problem for admission.
Hope this helps.
Good luck!