Diploma

You cannot apply for any further qualification India and abroad after completing Diploma. In case, PG Diploma is a 2 years full time course and has AICTE approval and AIU has granted equivalence to an MBA program, then it is fine.

You are not eligible to apply for MBA as you are just a Diploma holder. It is a Master's degree program and the minimum eligibility requirement is degree in any discipline from a recognized university with 50% marks.

I think, it is Rs.14 lakhs to Rs.18 lakhs for 2 years. Seneca College is the best for Diploma.

Both, BE and B.Tech are similar degree with only nomenclature difference. Therefore, you can do any degree based on institute reputation after Diploma in engineering.

All three are popular colleges under SPP. You can narrow down basis the fee, requirements, location, etc. You can also check the opportunities, internship, work placements, etc.

Hi Teerth,
The chances are good. But, you can contact the universities directly before you apply. Most of the universities do not accept 3 years Bachelor's degree. You can also check SPP colleges for PG Diploma programs.

It would be very difficult for you to get a visa approval from VO because under SPP category 8 backs are allowed in your entire program.
You can try to apply under non SPP category. You can also apply for some other country because Canada is very selective in picking up the students and they prefer students who holds a good academic record.