JEE

Akash is not recommended for JEE Mains and Advanced coaching else it's advisable for Medical and NEET Coaching only. For JEE Mains and Advanced coaching in Kolkata, you can prefer for FIITJEE, Resonance or Pathfinder.

Predict engineering colleges you can get on the basis of your JEE rank: https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign=8321427. In VIT placement are decent for civil but one should not depend on placements from VIT.
Most of the students go for a higher education. The highest pay till now in civil is 9 LPA which is rare.
Average pay around 4-5 LPA. Top companies visited are such l&T, Godrej and Tata housing. Mostly your role is such as site engineer and junior site engineer are offered. You have to have a minimum of 8.4 CGPA in order to even think about a job.

You probably cannot get any NIT or IIIT college. You should try for top private engineering colleges like Nirma university, JECRC, LPU, Chandigarh University, SKIT. Many more are there according to the location. Nirma University is the best option for you. For that, you have to fill up an online form that is available on its site. Then they will shortlist you according to your score in 12th and JEE Mains. Best of luck
Thanks.

Yes, you can definitely get NIT Jalandhar with the rank of 66685 in B.Tech Biotechnology. The 12th percentage is also calculated while taking the admission. Best of luck for your future and if there's any query, feel free to ask.

No, there is no other way/test for admission in these institutions.

According to me, you may get a seat in NIT.
But for a clearer idea, you should visit josaa.nic.in
and check previous years' cut-offs of NITs of home state and other states quota and also for various categories (general, OBC, SC, ST, etc).

Civil Engineer is one of the branches of engineering which has a very good scope of government jobs. Government departments like IPH, PWD, Electricity requires civil engineers and many posts are available in every state of our country. Apart from there, central government jobs are also there on the basis of IES exam in CPWD. So civil engineering is very good option for the aspirations who want to pursue government jobs.

No chance of getting NIT. But, there are also other good colleges
Try in them.
All the best :)

No, only NCERT books are not sufficient. You need to study much and more book than that. Some of standard book you need to study and solve them. More the practice, more you will be able to answer in the exam. Search for best books for JEE Advanced study.
Best of luck for future.

Your rank is good and you can get NITs in this rank. Go for the link below to find the Colleges of your choice and Branch:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor#.