Delhi Technical Campus, Haryana

Hi Vikas, DTC is affiliated to Guru Gobind Singh Indraprastha University, it is a new college, and hence there is no point of comparing it with other college in university. Placements track record is not that great, but that's not a precedent for the upcoming years. Academics and infrastructure are good here. Regards.

21 LPA is the highest package.

There is no way to make corrections in the registration form once you finally submit them on JAC portal.
You can do only one thing that either to contact JAC committee through email/calls or tell them your problem.

I think both the college are good for civil engineering, as the average package offered on both the institute are same. It is up to you.
Go and visit both the college for more insight.

All of them are good, every college you have mentioned has positive sides to it. You may even look into other colleges for options, here is a link for all approved architecture colleges across India - https://www.coa.gov.in/index1.php?lang=1&level=0&linkid=25&lid=26