MNNIT Allahabad - Motilal Nehru National Institute of Technology

CSE is the very popular branch in mnnit and in order to get you have to secure under 5000 if you belong to OBC category.

Yes, of course you are eligible. I would like to tell you, from this year on wards, the weightage of class 12th marks has been removed, so you need not to worry about your marks. Just prepare hard and enjoy.

For B.Tech, you have to give JEE Mains and secure a good marks approximately 200, if you are in a general category. For post graduate in engineering, you have to give GATE.

As I am from engineering background, so I do not know much about MBA but here is the link that will help you a lot. Also please visit to the official site www.mnnit.ac.in.

There are many companies that come for placement in MNNIT (approx. 200 companies).
For more details, visit:
http://www.mnnit.ac.in/tnp/

It depends on the branch you want to take and your category. Let me give you a rough estimate, if you belong to the general category and your rank is under 10K then you will definitely get any branch in MNNIT.

You can go through the official website for this www.mnnit.ac.in

According to my knowledge, there is no Diploma in MNNIT.

I don't think there is any Diploma course in MNNIT, only degree course are available.

First of all you have to clear JEE Mains with a good rank under 10k if you want to get into MNNIT with general category but here is no guarantee of getting your favorite branch. For this, you have to work hard.
Once your rank is out, wait for counseling and then fill the colleges in the priority you want to go to.
But at this time, I would suggest you to work hard and try to score as much marks as you can. "Do not shrink yourself to not only try, may be you will get a good IIT also.
Best of luck.