CBSE 12th

You can consider following options:
1. B.Com in Banking and Insurance
B.Com in IT
B.Com in Computer Application/Science
B.Com in Banking and Finance
B.Com in Retail Management
B.Com in Foreign Trade
2 BBA - BBA stands for Bachelor of Business Administration
3 Law - A combination of commerce and law can work wonders for your career.
4 BMS - BMS stands for Bachelor of Management Studies
5 Accountancy Programs6 Company Secretary
7 Bachelor of Foreign Trade
8 BHM and other hotel management programs

Hi,
If you want to take JEE then you need 75% marks in 12th (PCM).

I think that HA College of Commerce's admission procedure is based on HSC examination.

First, you'll have to complete your 12th with good marks in order to pursue following courses-
1. B.Com
2. BBA
3. BMS

You have scored pretty well in CEE. As far as I know you need a decent percentage in PCM, I guess around 54-60% if you are from general category. If you do have that you have a chance I suppose. You may check the information brochure given in the official website for the director of technical education of Assam or wait around for the counselling. But I would suggest you to keep options in other colleges.

Yes, you can give the compartment exam. Do your best in next exam.

No, the cutoff for Fergusson is quite high.

Here are the career options after 12th science:
MBBS
BAMS (Ayurvedic)
BHMS (Homoeopathy)
BUMS (Unani)
BDS
Bachelor of Veterinary Science & Animal Husbandry (B.VSc AH)
Bachelor of Naturopathy & Yogic Science (BNYS)
Bachelor of Physiotherapy

As you have score low in the NEET 2018. You cannot get government colleges. You should take a drop only if you are confident to crack it in next year otherwise you should not waste your one precious year. You can also try for some best courses rather than going in MBBS.