CUET

B.Tech  -> Yes Via Lateral Entry (LEET) to 2nd year

LLB ->Not directly First complete graduation (e.g., B.Tech) or check eligibility for 5-year integrated law courses

It is unlikely that you will get admission to the BBA program at HBTU as a general category student with a score of 180/250 in BST. The minimum eligibility criteria for BBA at HBTU requires a minimum of 55% in the 12th class. Especially given that the university considers CUET scores and other factors like the number of applicants and seats available. 

Not at all. It is an all India level exam, it's either offline or computer based exam.

If you are willing to take admission in Central University for any Bachelors course make sure to write the CUET exam and score good marks based on marks you will get seat in various participating university seats.

Earlier you can get admission in DU without CUET but nowadays CUET is necessary to take admission in DU. Some seats are reserved under the college administration and if you fulfill the criteria, you can take admission in that college of DU. You need some documents which helps in the admission in DU. 

No, students need to only clear either the CUET examination or the MUJEE examination to enrol into BTech at Mangalayatan University. Candidates who secured a high CUET rank can apply for admissions and directly go to the personal interview round.