B.Com

You can change the university if you have a genuine reason. But 2nd year B.A cannot make you eligible for 3rd year B.C.A.
You can pick B.C.A from some other university. Two degrees- one regular while the other correspondence, is valid and acceptable.
However, it is advisable that you consult the respective university/college and also speak to U.G.C officials for the right guidance.

If you have an interest in interior designing, then surely there is no harm in pursuing it simultaneously.

Hi Bibin,
My first question to you is what you want to study and where? Every country's admission requirements are different. You have to see if you have met the admission requirements, take necessary tests like IELTS or TOEFL, GRE and if you want to study in USA, arrange funds, etc.

Yes, you can do both course, if you are looking a training institute than Visit Koenig Solutions.

Hi,
Top 10 Distance Learning University for B.Com honors and BBA:
1. Delhi University
2. Tamil Nadu Open University
3. Annalmalai University, Directorate of Distance Education
4. University of Mumbai
5. Bharathiar University
6. Madurai Kamaraj University
7. Alagappa University
8. Punjab University
9. Gujarat University
10. Karnataka State Open University

11th class marks are not counted for admission in B.Com or B.Com Hons. You are advised to study hard and score very high in 12th board to seek admission in B.Com Hons Commerce. All the Best!