IIM Lucknow - Indian Institute of Management

Yes, the marks are seen and sometimes part of evaluation criteria too. Depends from IIM to IIM

IIM Lucknow. It's not the best, but should be better than st. Xavier in terms of various parameters. Although both the colleges are, I'm sure, well-equipped with all necessary facilities, etc. Faculty and placements at IIM Lucknow are better.
Having said that, its not harmful to take advise from St.Xavier's student as well.

It is difficult to compare as one cannot personally know both colleges very well. I can give you some insights about IIM Lucknow, though.
Campus- The campus is beautiful, with every possible amenity that would be required. Huge library, spacious rooms, gym, swimming pool, sports ground/court, etc.
Food- IIM Lucknow mess food is good. I think you can compare any college's food with ours and we will win for sure!
Academics- No doubt IIM Lucknow is better.
Placements- Again, there is no match!
Probably, your field of interest might help you compare the two colleges. Taking opinions from any student of SP JIMR might help as well.

As of now, you must focus on your studies and get good grades, while you are doing your under-graduation. For CAT prep, make reading books, news, article as a daily habit. Also keep a good command over your communication skills, if you feel there is scope for it. I think this will do as of now. You may take up CAT class later on.

Sorry! With such scores, it is not possible. However, do try other good MBA colleges.

Chances are high. Kindly interact with the admission officer of IIM-L.

Your interview score will be added to the overall scores to calculate your final score. That is where your academic score will count. Other than that, you might be asked questions based on your graduate courses in the interview

If you have work experience, then you should be in a position to answer anything that they ask you about your job. Have a look at the major current affairs and form your opinions on that. Other than that, prepare questions like tell me something abt yourself, strengths and weaknesses( with examples from each). You should know about your college courses, if you passed out 1-2 years ago. Also, practise GDs. We were given a topic, where we had a wat first, and then a gd on the same topic.