Engineering

No, with this rank, you cannot get admission in this college. try for some other private college.

Yes, slide option is present in WBJEE.

Computer Science has a massive scope in today's world than any other branch.

Yes, according to me, you should go for IIIT and not for IIT as CS has more scope than mechanical and the college doesn't matter in comparison to branch, what will be the benefit if you get a job in mechanical and not get promotion due to its very less scope.

The first year of engineering is common to all in every college. In the 2nd year, you will have:
Mechanics of Solids
Fluid Mechanics
Applied Thermodynamics
Material Science (Metallurgy related)
Machine Design and Drawing
Kinematic and Dynamics of Machines
I. C Engines
Production Techniques
In the third year, there will be:
Heat Transfer
Production Techniques
Advanced Mechanics of solids
Engineering Optimization
Mechanical Vibrations
Prime movers
Computer-Aided Design.

Yes, you will get admission in 2nd year. of B.Tech as lateral entry. For lateral entry, normally you have to appear for Lateral Entry Engineering Test (LEET). You must have a minimum of 60% marks in Diploma to appear for LEET. Incase If you have not given LEET, then try for admission in Private Colleges in your area.

Hi Sushmit,
No, you are not eligible for the above course.
Mandatory Course: B.E. / B.Tech (Civil Engineering, Structural Engineering, Environmental Engineering, Agriculture & Farm Engineering, Mechanical Engineering, and Environmental Engineering).

Check this link to about ABESIT-Ghaziabad for CSE in terms of placements and other necessary details:
https://www.shiksha.com/b-tech/course/b-tech-in-computer-science-engineering-abes-institute-of-technology-abesit-ghaziabad-249649

Kindly visit this link for the detailed information:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor