CBSE 10th

No, you will not get or face any problems while applying for a visa in Canada, and you have a good percentage in class 12th so all the best for your future.

Percentiles matter lot for the admission in the colleges. as your have scored very good percentile and in Class 10th and 12th also you have scored very good so you will definitely get very good college with this percentile.
There are Various MBA colleges that offers admission in this percentile only you have to do well in GD/PI.

Refer the following link of college review made by shiksha https://www.shiksha.com/college/university-business-school-chandigarh-panjab-university-21440/cutoff. Please kindly have a detailed review about the college so that You will get a clarity about the college popularity rating, features, fees structure of college, faculty rating of the college, value rating of the college based on fees paid and placement rating of the college. All the best for your future.

There are Diploma/certificate courses available in game designing after 10th or 12th in India.
1. Certificate in gaming
2. Certificate course in Game art & Design
3. Diploma in game design.
4. Diploma in game design and integration
5. Diploma in Game programming
6. Diploma in game development etc.

SEE its depends on your school if he allowed you to give then its okay, you should ask first form your school.

Yes. Percentage doesn't matter if your doing it from any private institution. You just have to be dedicated as well as interested in your learning.

Yes you can do MBA
The minimum eligibility criteria for MBA is a Bachelors degree from a recognised university with an aggregate of 50% (45% for SC/ST/PwD). The eligibility criteria varies from college to college.