Career

Yes, MBA will enhance your CV and improve professionalism. If pursued from a good college, it will surly give u the edge over other mech engineers.

Check out BSc courses. If there is any subject you are interested in, then take up its Bsc course. After Bsc, you can go for MSc. Other option is that you can go for BCom or BBA or BA now. Choose well.

Generally DC are from IAS cadre. You can become direct IAS by appearing for Civil Services Exam conducted by UPSC. Every state conducts it's own Provisional Civil services examination conducted by state Public Service Commission . Those who clear PSU exam are eligible to be prpmoted yo IAS cadre after few years of experience. Once such officers become IAS then they are also eligible to become DC.

Yes, there are so many colleges in India offering architecture prof=grams in under graduation. For example JNAFAU is an architecture college in Hyderabad affiliated to JNTU. So many people will appear for the entrance examination conducted by that college who are interested in architecture with the different background studies.
You can apply to colleges by writing the entrance examinations conducted by them and you can also appear for B.Arch exam conducted by government.
I hope the above information is related to your query and help you to find a solution in one way or other. All the best!

Both BBM and BMS are similar courses. Both courses will help you to get supervisory role in business enterprises. To start career as Business Manager, you may have to study up to MBA from a reputed B School.