Colleges in Dehradun

It may vary every time. Petroleum (Upstream and Downstream) Computer Science (Cyber Security and Cloud Computing) Fire and Safety Are one of the top ranking placements providing B.Tech branches in UPES.

Yes, you can but it is based on first come first serve basis.

It is a good branch in UPES with excellent placements. You can go for it.

UPES has a good placement record of mechatronics branch and students from UPES get offer from good companies like:
Birla Soft Technologies,
IBM,
Infosys,
Aveva Softwares,
Weatherford Drillng,
Caterpiller,
Cummins,
Escort Ltd,
HERE Maps,
JK Tyres, etcetera.
Around INR 4.5 LPA is the average package that a campus placed mechatronics student gets.

You get to do the internship from the college itself. You can grab it in GE (Oil and Gas).
Industrial tour in Refinery, LNG Terminal & an onshore gas processing plant.
The placements of both the branches are excellent since both are the core branches of UPES.
You can check UPES Website for the reviews of these branches written by the alumni.

So you have two universities to compare for MBA-HR.
Let us talk about Amity University:
Pros:
Good Course Curriculum
Good Infrastructure
Cons
Placements: This is disappointing because 4 out of 20 students gets placed with an average package of 3.5 LPA. The other has no option left than picking an off-campus job of 15k-20k.
UPES
Pros:
Excellent Course Curriculum and Infrastructure
Placements of this branch in UPES has always been trendsetting.
Cons:
The university just lags behind in terms of high fees.

Please refer to the link provided below for an exhaustive list of college which offer B.Sc computer science courses from Dehradun. You should be able to navigate to a college of your choice using the filters on the webpage. Additionally, you can also download their brochure which contains accurate details regarding rankings, reviews by students, alumni etc.
https://www.shiksha.com/science/colleges/b-sc-colleges-dehradun

Please refer this official FAQ for your every query about the college recognition.
http://www.upes.ac.in/FAQs

No, UPES doesn't have any specified course for mass communication neither in Undergraduate nor in Postgraduate. However, that is taught throughout in each course offered.