NATA Scores

Opt for the course that you love the most and are most passionate about and analyze the future work conditions, scope and growth prospects before taking admission.
You can also opt for psychometric test comprising of Aptitude, personality and career interest to clear confusion. Scholarship depends on the college but with 162 marks, it seems quite difficult to get scholarship.

Once the date for corrections is over you cannot make any changes.

The procedure of normalization of NATA-2016 score will be put on NATA web site in due course of time. An attempt will be made to normalise (with respect to NATA-2017) the score of NATA-2016 qualified candidates seeking admission in the session 2017-18 in order to specify their position in order of merit for counseling purposes. Such guidelines would be based on statistical analysis and the Councils decision would be final in this regard.

In NATA, basic drawing skills, stroke confidence, your aptitude skills are checked.

Yes, you can if you have secured a good rank in NATA.

Chances are very slim. It will depend on your rank.

Selection in MSU is done through ACPC. There is only one seat for CBSE in MSU. For further details visit: http://www.jacpcldce.ac.in/archi.asp

IIT Roorkee offers admission on the basis of AAT (Architecture Aptitude Test).
AAT is an architecture entrance exam for admission into IITs. Moreover, for appearing in AAT you have to clear JEE Advanced also. To appear in JEE Advanced you should have cleared JEE Mains paper 1.

Admission in a government college for B.Arch is considered at 90+ in NATA and 300+ in JEE Mains paper 2.
So, you are advised to google the cut-off for govt. institutes.