Engineering

People do diploma for getting average job means a monthly salary of 25k maximum. Many people after doing diploma do B.Tech, so I will suggest you to take science and give intermediate exam then go for B.Tech if you are not in hurry of job.you can get a better job in the future.

DTU CSE is more better than IIT, Roorkee. CSE placement is also very good in DTU.

Yes, you can apply. To get admission, either you have to crack GUJCET or JEE Mains with good rank.

As per your rank which is 83167, it is really difficult to get your number in 2nd counselling. You can also check last year cutoffs and you check where students with the same rank as your stand last year. even though you can wait after checking the cutoffs, if there is any chance for getting a seat

Sorry, but you will not be able to get into Nirma Unversity with these marks. Though the selection is dynamic and dependent upon the students applying for it and hence changes every year, still the cutoff for CSE/IT is around 2k and the least non-technical branches is around 80k.

If you want to take admission in NIT/ IIIT / IIT /GFTI, then you need to qualify JEE Mains to get admission.

IIT Guwahati is better as it is one of the old IITs and it enjoys better placements, academics, culture, campus life, etc.