B.Sc

Apart from a decent +2 score (75 %+), you need to sit for IELTS in case you are looking for high ranked universities in the UK. SAT exams are not required for the UK. It's mostly IELTS exam that you need to clear with overall 6.0 bands in most cases. Let me know which program you wish to apply to so that I can suggest a few universities.

There is good scope after B.Sc. IT because it is IT field. Also, you can pursue higher studies after B.Sc. in IT, e.g. MCA, M.Sc. IT, etc. You may get job in IT sector after the completion of your B.Sc.
You have career options in this field as web designer, junior software developer, database admin, backend developer, graphic designer and many more.

It totally depends on you. If you think that you will go in the teaching line, then you must do B.Ed after B.Sc, but if you want to do research opt for M.Sc.

If you are planning to go for higher studies after B.Tech, then opt for electronics engineering. Electronics engineering has very narrow scope in India. You should opt for B.Tech in IT or CSE instead of electronic engineering.
B.Sc in IT is also a good course, but you will get benefited by pursuing B.Tech.

M.Sc CS is better than MBA because you have a very good CS background and MBA is a management course.
So, M.Sc CS is good. Also, M.Sc CS offers very good career opportunities.

You need to appear for CAT, MAT, CMAT or PGCET exam after B.Sc to get admission in a college for MBA. Try to score good marks in CAT exam to get admission in one of the top B-schools.
If you have work experience, then it will work as an added advantage.

You may get admission either in Graphic Era or Dev Bhoomi Institute.

Your entrance exam scores will totally decide your admission and not your graduation scores.