Diploma

Hi Fahad, this is like comparing apples and oranges. You must decide what you want to study and identify your interest, both MBBS and engineering are different so choosing either one of these two makes little sense, also you are from a biology background so I am not even sure if you can catch up with engineering topics. A very strong foundation in mathematics would be required. You may explore more subjects related to medical sciences or opt for a B.S in a biology or botany or even wildlife science. Pharmacy, vet. science, nursing etc are other options. The decision would be yours.

Hi,
Have you completed PG Diploma?

PGDM is better, if done from reputed institutes like:
1. IIMs.
2. XLRI.
3. BITs.
4. FMS, etc. as these are all industry driven course.
You may also look for MBA abroad to have a global exposure. MBA in Indian universities are not well designed.

There are many colleges in Ontario that provide tourism courses.
You can check the below mentioned link:
http://www.ontariocolleges.ca/SearchResults/CULINARY-HOSPITALITY-RECREATION-TOURISM-TOURISM-TRAVEL/_/N-lqh5

What you mean by abroad? You must be specific with your country choice. If you haven't made a choice yet, you can check websites like QS World Ranking, Economic Times, Times Higher Education, etc. for the university rankings worldwide. You will have the idea. You need to take IELTS or TOEFL as well to apply.