CBSE 10th

Hello Prince, it's very nice to hear that you have already fixed the aim of becoming an engineer. As a first step, you need to study really well for next two years with understanding the subject being the theme. Must score at least 75% in 12th and thereafter can apply for B.Tech programme in a reputed college.

You should firstly find out and ask yourself that in which field you are most interested? What you want to become? How do you want to see yourself in future? Go according to these question, You will surely get the best field for your bright future. All the best.

Probably not, but you may try for some other colleges.

I think you can't pursue Computer Science because it is a Science stream course. You can go for CA if you are interested in accounting ormay go for IIM if you are interested in management or business studies.
On the other hand, IAS is most difficult but if you are interested in extensive study and are a seeker of knowledge, you may go for this.
So all of the courses totally depend on your field of interest.
Your percentage is good, so you can be admitted in a reliable course which you want to do.
However, universities have some other criteria, so it varies. All the best.

If you are not interested in Science stream, you can opt for commerce stream or arts stream. There is a wide range of interesting subjects to choose from in arts stream.
But before opting for commerce or arts stream, make sure you are not interested in Science stream as you can't change it back and forth. Do a little introspection.
If you like biology, the medical profession is also highly sought for, just that you have to bear with physics and chemistry for a few years.
Good luck for your future!

Yes, you can do it. Commerce graduates have good options as follows.
M.Sc. Finance
M.Sc. Corporate Finance
M.Sc. International Finance
M.Sc. Banking and Finance
M.Sc. International banking
All Masters programmes abroad are specialised programmes and focusing on a specific field. This will make you more employable.

Well, the thing that matters is your interest. Whichever field you're interested in, go for that.

Yes, if you want to do a job then you can but you can only pursue BA or distance mode of education type course. You can't pursue any professional courses because after the supreme court order none of any pro courses can't be done via distance mode of education.

Yes, you can get admission though your UPSEE marks are not good enough to get you a seat in good college. Try to get any good private college if you can.