MAT

Dear Sagar,
I would like to congratulate you as you scored good marks in both the respective entrance exam. It is the right time to apply for institutes. JIMS, Rohini provides dual specialisation programme and you can opt for that. It's a good combination. You can see their placements:
https://www.jimsindia.org/placement-record-2015-2017.aspx

Yes, there are chances for SIESCOMS.
SIES has equal credit for GD/PI as well as for the entrance test as your entrance exam score is not so good. So for SIES you need to more concentrate on GD/PI process.
Last date of form filling is 4th April.
Further information available on:
http://www.siescoms.edu/

Your MAT score is really good. Yes, you will get admission, it doesn't have anything to do with work experience.

Hi, Yes you can get. PUMBA MAT cutoff is around 600 marks in MAT.

Yes, you can get admission in Alliance University.

For doing MBA or PGDM from well renowned institutes you have to give entrance exams.
It may be CAT, NMAT, SNAP, XAT or MAT. Without giving entrance exams you won't be allowed to go in good institutes.

You should try for Symbiosis or SP Jain for best results.

Please confirm once with college if MAT score is accepted.

No, as per the criteria, academics should be 60%+ throughout.

You stand a chance for sure. You have not mentioned about your CAT score, which may also be a requisite.
All the best.