CBSE 10th

You can join any private institute for interior designing and after 12th you can do a certified Diploma of 3 years in interior designing.

No, you can't take direct admission after 10 in HM. You need to clear your 12th and then only you can apply for HM.

You may sit in the placement process with your class 10th and graduation marks as your aggregate score would be in the 60s. However, there is a zero-day in the placement season when 13-14 companies come to campus which does not ask for any eligibility criteria. You can seize that day my friend.

The eligibility of the course is 10+2
Students can apply for prospectus and application and block seats by paying registration fees. For B.Sc. And M.Sc. Degree programs the applicant must qualify in a test conducted by the institute.

You should complete your 12th here & then apply for German universities.

You just need to get a mere 80-82 percentile to clear the cutoff and then you have to excel best in the IRMA Aptitude Test and then convert it with your expertise. Upvote and follow if found useful.

Since you have not mentioned your university, it is quite difficult to say. But, in general, it sure does seem possible. A lot depends on the marks of people around you (as IIM Bangalore grades your marks relative to others and then gives your application some points). Anyway, it does seem possible, just score as high as possible in your CAT.