Diploma

https://www.shiksha.com/college/svc-sri-venkateswara-college-dhaula-kuan-delhi-23925/admission
have a look onto this.

Yes, it is possible if you have completed your class 12th. You can take bachelor degree

Hello Ritesh,
If you had mentioned your home state then I would have been able to give you list of colleges. However, you can yourself ask Shiksha Assistant or check on their webpage colleges in your state as per ranking.

There is no such criteria of merit, it’s just that students have to clear their 10+2 exams from a recognised board of education.

Yes, there is a 2-year advance Diploma in fashion Designing in JD Institute of Fashion Technology.

Yes, you can get admission in Reliance Education: VFX and Animation Academy for Game Testing certified course as the eligibility criteria says that candidates who have completed class 10th or above are eligible for this program.
Candidates with awaiting result are also eligible.

Hello Lakhan,
To get admission in Modern Education Society's College of Engineering, candidates need to qualify either Maharashtra common entrance test (MH-CET) or JEE Mains for B.tech & B.E courses.
The minimum eligibility criteria is 10+2 passing certificate from a recognised board.
So, your diploma

Yes, you can do travel and tourism course.
Firstly, complete your Bachelor's degree and then do your Master's degree in country A and travel that country. If you want to pursue doctorate then go ahead with a great institute in country B and travel the country.

Check this out:
https://www.shiksha.com/engineering/colleges/diploma-mechanical-engineering-colleges-Bangalore