Guitar

Yes, you can do this course from Government College of art. You will have to pay around INR. 11,000 per semester.
Good luck.

Yes, there are many colleges in India that offer a Diploma in music. You can refer to the list of colleges here https://www.shiksha.com/arts-fine-visual-performing/music/colleges/diploma-courses-delhi-ncr?cr[]=10&rf=filters&uaf[]=location.

SPPU teaches both classical and western music. You can learn so much from here. Good luck!

You can choose the subject according to your interest.
Please visit the link to know about the courses offered under B.A(Hons.):
https://www.shiksha.com/university/rabindra-bharati-university-kolkata-25277/courses/ba-bc

No college considers music in main four subjects.

It can be either of these depending on the facilities available with college. Once you enrol for the course, you will be able to get a better insight about this or you can get visit the college and get in touch with the current students.

Hello,
Try the following:
Delhi School of Music, Chanakyapuri
Brij Music Academy, Rajendranagar
Saraswati Music College, South Delhi
YMCA, Connaught Place
If not Delhi, kindly tell the desired location.
Regards.

Hello Saurabh,
I would suggest you the below colleges-
AAFT Noida
Amity Noida
Hindu College North Campus
Ramjas College North Campus
Please refer to this link to have detailed information about these colleges-
https://www.shiksha.com/arts-fine-visual-performing/music/colleges/colleges-delhi-ncr