Accounting & Commerce

Yes definitely you can get admission with this percentage in GGDSD College. Also you will get some 1 or 2% more if you have maths.
ALL THE BEST

You can start preparing early. But, in order to write the exams, you would need to be a graduate.

Definitely GLA University is one of the best university in Uttar Pradesh accredited with grade A, I've done my graduation from here itself in B.Com (Hons) and trust me I've got the best exposure here. Till my intermediate, I was not that good at academics but I always had interest in acting and writ

The last year minimum CAT cutoff percentile for top 3 Iims are given below in asked category for an idea.
1. IIM Bangalore :
a) Sectional cutoff : 65
b) Overall cutoff : 70
2. IIM Kolkata :
c) Sectional cutoff : 65
d) Overall cutoff : 70
3. IIM Ahmedabad :
e) Sectional cutoff : 60
f) Overall cutoff : 7

Yes, you might get a seat in 2nd or 3rd Counselling, so please take another college in your Backup options like DAV10, PGGC11, PGGC46, MCM DAV.
ALL THE BEST

See without Maths it is very difficult in GGDSD College, also NSS carry only 1% weightage in the overall percentag, So i think you should try for PGGC11, PGGC 46
ALL THE BEST & FEEL FREE TO ASK ANYTHING

GGDSD College is not possible with this percentage, you can try for PGGC11, PGGC46
ALL THE BEST.

Without maths it is quite difficult in GGDSD but you can try for PGGC11, PGGC46. But still fill the form for GGDSD College too may be you get a seat in 3rd or 4th counselling.
ALL THE BEST & FEEL FREE TO ASK ANYTHING

See as you are a NON UT, B.Com is not possible with this percentage, but you can try for BBA in GGDSD College definitely that is possible with this percentage.

No, you need to have studied and passed maths in class XII. You don't need to include it in best 4 , but you need to have it as one of the subjects in class XII.