CBSE 12th

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.

You can consider following colleges:
CSKHPKV-Chaudhary Sarwan Kumar
Himachal Pradesh Krishi Vishvavidyalay Public University, Palampur,GC-Government College Palampur
Himachal Pradesh University, Palampur, India
SCVBGC - Shaheed Captain Vikram Batra Government College
Himachal Pradesh University, Palampur, India
Ferguson College, Pune
MS Abasaheb Garware College, Pune
Swaraj College of Commerce and Computer Science, Pune

You have some other options like BCA (Bachelor of computer application), B.Des, B.Arch, etc. You should prefer one of these courses as per your interest in the field or course. You can also go for interior designing field through B.Des course. All these fields have wide scope for future.

As you are interested in computer science field you should either go for B.Tech CSE or for BCA which have wide scope. Computer science engineering is the most demanded in modern era.

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.