West Bengal

You can check the below mentioned link:
https://www.shiksha.com/mba/colleges/mba-colleges-in-siliguri

You can get into VLCC Institute of Beauty and Nutrition to pursue beautician course.

Hi,
The best may differ with people, you need to check your interests and then tag along. A demanding career option may not be suitable for you, if you are not meant for the role. So, please figure out your interests and plans, know what you want. Can you mention your stream?

You can join NIIT for SAP training in Haldia.

There are a number of coaching centers among them Career launcher, TIME and IMS are reputed ones. Since you are in Patna, you can prepare there as well. Patna is a hub for coaching and you can find a number of institutes in Ramna Road, Kankadbagh and Bhikna Pahadi area.

There are no substantial good colleges in Kolkata however you may take admission in The Institute of Mass Communication Film and Television Studies.

80 percentile has been the trend generally for general category.

No, it is not a good option if you take direct admission they will ask you for more fee but if you go there with your scorecard of any entrance exam, it will be fruitful for you.

Here are so many government and private institutions for Diploma in mechanical engineering. The best government colleges are Balure Silpo Mandir, HIT, BIT, etc. and top private ones are TPI, Institutions of Technology, Brainware, JIS, Techno India (Saltlake), etc.