Colleges in Himachal Pradesh

They all come under MIT-WPU.

Chitkara University is a no.1 choice for B.Tech in Punjab. Chitkara University has a really good reputation & university established in the year 2002. In the latest survey by CSR-GHRDC Engineering Colleges Survey 2017, Chitkara University has been ranked top in Punjab among the top engineering colleges. See the source for confirmation: http://www.chitkara.edu.in/events/csr-ghrdc-engineering-colleges-survey-2017-ranks-chitkara-institute-engineering-technology-11th-among-top-engineering-colleges/

College change or branch change after the first year is completely dependent on college norms, some college allow it and some won't plus you need to have good scores in the first year to apply for the same. For further details contact the college authorities.

Can I know your rank in JEE Mains Paper 2?

You have a chance of getting admission into this NIT in B.Arch course and that too only if you belong to Himachal Pradesh because of the last year's B.Arch sixth round cut-off closed at 12000 rank for Home State OBC.

Maharaja Agrasen University, Solan is a good option for you.

Doing MBA in BA LLB from APG University is very good. it is a nice option. Placement assistance is also good in APG.