BCA

Yes it is possible. And fees structure depends upon the college but in IGNOU it is free.

Yes, a 4 year gap allowed for admission in BCA course in DIT University but you have to give gap affidavit from court.

Brainware University and JIS university both are good for BCA. But if you compare these two colleges for this course then you will see that BRAINWARE is better than JIS on behalf of student reviews. The placement of BRAINWARE university is also more than JIS. This year Brainware has achieved 98% placement. The final decision is yours but before that visit, both colleges (If possible) and then make the final decision.

Christ university is best for BCA.

Hello Old, The college did not provide good placements in the year 2019. Placements: During the completion of our course, only 2-3% of the students opted for either Masters or more Diploma courses. The highest salary package offered was 6 LPA, and the lowest salary package offered was 3 LPA.

I am providing below a link on how much your total course fee will cost in three years to get admission in this college. Please take a look from there.
Link - https://www.shiksha.com/college/christ-college-pune-viman-nagar-34619/courses?rf=filters&bc[]=33&uaf[]=base_course

Yes, a BCA student can do B.Arch after completing graduation, no problem, but he has to get more than 80% marks in graduation level and complete graduation.