Diploma

https://www.shiksha.com/humanities-social-sciences/languages/course/amp/diploma-in-german-sri-venkateswara-college-dhaula-kuan-delhi-257512
You are a bit late now. Try other colleges.
https://www.shiksha.com/humanities-social-sciences/languages/course/amp/diploma-in-german-acharya-narendra-dev-colleg

You can get more information about it here
https://www.shiksha.com/b-tech/course/b-tech-lateral-entry-college-of-engineering-Pune-shivaji-Nagar-204728.

No. You can get admission in first year though. You can only get lateral entry in BE or B.Tech. Your Diploma will be considered equivalent to 12th for B.Com.

MBA in India is 2 years and is considered a Masters Degree. In foreign nations however, it can range from 1 year to 3 years. You will have to check each college individually. Also, not all courses are considered a degree. You will again have to confirm that for each college.

College change or university change after first year is completely dependent on college and university norms, some university allow it and some won't. Plus, you need to have good scores in first year to apply for the same. For further details, contact the college authorities.

Hi, Could you please revert with your current qualification?

You can go for IT organizations, fashion designing, painting companies etc. Water supply, HIL, BHEL, Communication services, BCPL, Railways. Pursue a certificate course from A. M. I. E (Associate Member of the Institutions of Engineers), you can also go for NIFS.
Best of luck.

You can get admission for B.Tech 2nd year. You can't get admission for BCA.

Please go through the eligibility criteria:
https://www.shiksha.com/it-software/course/post-graduate-diploma-in-computer-application-sam-higginbottom-institute-of-agriculture-technology-and-sciences-Allahabad-186577.