CBSE 10th

Yes, you can get admission in IITs through lateral entry program. There are opportunities for lateral entry in which admission is given directly in 2nd year of B.Tech if they have pursued Diploma or Polytechnic. You can check IIT's website for the latest updates on lateral entry program.

For admission into XLRI , you need passing grades in all these standards you have mentioned. There is no minimum cutoff mentioned as such but a higher spectrum is generally favorable or required. I would say that more than 90% of students who have got admission into XLRI would have more than 55% in 10th and 12th

Diploma and Bba are two different streams. Diploma in mechanical and bba in travel seems no relevance, so go after engineering in mechanical stream for better opportunities

yes you can join different branches of diploma engineering as a professional course. It is a three year course after which you can go for job or B.Tech/B.E. Another option is +2 to continue for your study

If you want to do civil engineering after 10th class then you can join three years diploma course from Government recognised polytechnics.You have another option also you can choose NORTH EASTERN REGIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY (www.nerist.ac.in) also. All the best.

Opt for coaching if you want to qualify competitive exams with good grades.

You will get calls from top B-Schools.

It isnot possible to directly get into ME with diploma. You have to be an graduate in engineering.