Lateral entry

No, it's not at all possible because your score is not so good at least minimum eligibility is needed. As CSE is a very demanding course it's not possible for you to take that branch. You better choose any other.

No. There is no lateral entry for IITs and also for NITs.

For this rank, it may be difficult to get government seats in DSCG if you are from general category. If you have a reservation then you may get government seats.
Good luck.

In respect of reservation of seats for SC /PWd and various other categories, seats varies according to the government of West Bengal rules of the concerned university, prevailing at the time of admission will be followed. Such reservation are only available to West Bengal Domiciled candidates. And, almost 20 seats will be there for SC category students.

I think distance learning is an option for this type of situation. Sikkim Manipal University is one of the best institutes for this. Kindly check the distance learning programme of the universities.

For technical courses AICTE recognition is must
For non-technical courses UGC recognition is must, as simple as that. If you are studying engineering, Diploma, see your college affiliated to AICTE, if you are doing BA B.Com B.Sc. See UGC recognition.

Government College of Engineering, Amravati
Government College Of Engineering, Aurangabad
Government College of Engineering, Karad
Government College of Engineering, jalgaon
Government College of Engineering, Chandrapur
Government College of Engineering & Research, Awsari Khurd
Government Engineering College, Yavatmal

Yes, definitely, you can try for it. I think your score is good which will help to get the college easily.