Engineering Entrance Exam

Yes, you can drop a year but only when you think that you will do better in the next year or you can get admission in the college of your choice.

You should score around 150+ for CSE and ECE.

With the marks mentioned by you, it won't be possible.

Your rank is very low. You have less Chances of getting this college. Try to get colleges of your state in your locality if you are interested in engineering. Try JEE college predictor to get more information and insight about college which you can get on the basis of your rank-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795.

Kindly visit the link mentioned below:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795

You can get NITs. Try JEE college predictor to get more information and insight about college which you can get on the basis of your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795

If your rank is within 30-50K then only you will be eligible for NITs. You have to appear in counselling of JoSAA through which you will be allotted seats in the college like IITs, IIITs, and NITs. For your state level counselling, you have to appear in State's counselling platform. Try JEE college predictor to get more information and insight about college which you can get on the basis of your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795

You can get government college of your state (maybe) NITs. Try JEE college predictor to get more information and insight about college which you can get on the basis of your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795

No, you cannot take admission in IIT without qualifying JEE Mains.

As per last year's trend, cut-off ranks for disciplines in Tezpur University were 20,000-40,000 for general category so it will be bit difficult to get a seat. Also, check the below link:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign=8030745