Pilot Training

Both the profiles that you have mentioned here are way different from each other. There is nothing comparable between them. Hence, there are only and only difference.
Commercial Pilot flies the plane and does the operational duty for the airline whereas someone who has done B.Sc. Aviation might be working for any department as per the company requirements. It may be operations, ground handling, ramp duties, cargo, hub control, etc.
B.Sc Aviation is merely a graduation degree which allows you to call yourself a graduate and hence, eligible for any job that requires it's candidates to be a graduate.
And, on the other hand, Commercial Pilot Course is a professional training which helps you earn a Commercial Pilot License and hence, you qualify to apply as a pilot for any airline that is hiring fresh CPL pilots.
I hope the things are clear now!

In a year, based on recent statistics, approximately 26 lakh graduates pass out of the Indian Education system. Can you guess how many of them ended up with a job (A job commensurate to their education) on completion of their graduation? 30%? 20%? Nope. An appalling 8%.
Of the 15000 odd CPL holders in India, roughly about 5000 are working in the airlines. So, you do the math and figure out, if it is as tough as otherwise to get a job.
Leaving the stat aside, how tough or how easy it is to make it big in any career, depends predominantly on your caliber and the quantum of effort that you put in to equip yourself to be among the best. I have come across tons of CPL holders who whinge about the competition in the job market in India. To them, I state one simple stat. In any recruitment drive conducted by a major airline in India, roughly 4000 odd CPL holders compete for 100 spots (which has been the case for the past 5-6 years), which means roughly 1 out of every 40 get a job. And, there are six major airlines, some of which conduct such recruitment drives all the year around. When you graduate with a degree from a college, you are looking at a competition of 1 in 10000 to land yourself a decent job. So, decide for yourself as to where the competition is at it's toughest. If you don't have it in you to be the best one among 40 candidates, then it is a tough luck. If you have it in you, then you are looking at an illustrious career, with everything being fed to you on a silver plate all through your life.
Yet again, people keep complaining, that only if you have a jack, you would be able to get into the major airlines, i.e complete BS. I have seen a lot of my friends get in simply without that, simply because they persevered. I myself had none, yet have worked with two of India's major carriers. It is sure, that jack works in aviation (where the hell doesn't it , in India), but that's not everything. You can be your own jack to get into an airline.

The only educational requirement for CPL training is 10+2 with PCM as its subjects. No graduation or post graduation is required.
In case you do not have PCM at 10+2 level, you shall stand ineligible for the course.
There are although provisions for those candidates who do not have PCM at 10+2 level and are interested in pursuing CPL training. They should appear for maths to complete the trio of PCM in the next session of board exams. After clearing maths at 10+2 level, they shall qualify with PCM and hence shall fall eligible for the course.
The other may remain as additional subjects, although they are of no use.
Like I mentioned earlier also, no Graduation or Post Graduation is required to pursue CPL training, lnless you are looking to join the defence forces as a Flying Officer (Pilot).
In defence services, they require graduation if you go through AFCAT or CDSE.

Definitely, you can!
But foreign airlines hire expat pilots with certain specific requirements. Usually, the requisites include:
# ATPL
# Flying Hours at least 1500
# 500 Hrs on type
# English Language Proficiency Level 5
# Class 1 Medical
The license requirement may be ICAO or FAA depending on the operator's needs.
So, before you apply for an airline like Qatar you will have to obtain at least the minimum flying hour requirements and Medicals. License conversion can be done based on their requirements.
They too have different selection procedure and pay scales for those pilots who join them from outside their home nations.
The work culture is designed to make the newcomer feel comfortable and adjust smoothly. To and fro tickets for home travel are provided. Accommodation and other important amenities are also taken care of.
Indian CPL and ATPL are ICAO licenses, hence you can be eligible to apply to any nation where they accept such licenses provided you completed the other requirements also.

Training to become a pilot is obviously an expensive task. Hence scholarships and freeships help the candidate to offload their financial burden.
In India, government flying clubs support schemes which are offered by various government institutions who finance loans for candidates who are looking for CPL training.
For general category candidates, who fall under a certain defined value of family income, Nagar Nigams have schemes for freeships are loans.
For those who belong to the Other Backward Castes, Schedule Tribes and Schedule Castes, their respective commissions have schemes to offer loans, scholarships and freeships to candidates belonging to their respective commissions.
Under such schemes, the funding is provided by the authority directly in the name of the flying schools where the candidate has enrolled himself.
This process involves a lot of documentation and paper formality. The file hence created is made to go through various sanctions and approvals. Hence the process becomes lengthy and time taking. So you to be really patient and calm if you are looking for any such scholarship or freeship or loan from the authority.
I hope I have given you enough information about the subject for you to decide wisely. Good Luck.
Any further query is most welcomed.