SRM Institute of Science and Technology, Kattankulathur Placement

I would suggest you go ahead with SRM rather than Hindustan. reason:
SRM has better ranking and infrastructure
Better Professors
Better Placements than Hindustan.
So, I would suggest you go ahead with SRM.

It is definitely good. You can apply and there exist a placement cell.

Yes, obviously SRM University, Chennai is better in terms placements. Last year in 2017, 548 companies visited and for 2018-19 batch so far 300+ companies have already visited and many more to come.

As we all know, SRM University is well known for its placements. As far as CSE department is concerned, the placement ratio is almost 75%. The average salary package goes around 4 to 5 LPA. And the highest around 25-30 LPA. But the package someone is offered, also depends on performance during the interview. For better understanding, click the link:
https://www.shiksha.com/university/srm-institute-of-science-and-technology-kattankulathur-chennai-24749

I feel SRM University is a better option for MAMC in terms of placements. Also, I would like to endorse SIMC, Pune and Bengaluru.

You can see the placement in SRM University through the following link:
http://www.srmuniv.ac.in/journalism-masscomm/placements.

I can tell you about SRM University. It has 100% placement in CSE department. Many big firms recruit students from SRM University like Cisco, Amazon and E&Y.
You can check the placement records here.
http://www.srmuniv.ac.in/cse/placements/2016-2017
http://www.srmuniv.ac.in/cse/placements/2015-2016

If you want to go in designing field than you should choose mechanical and if you are interested in automobile and its functioning than you should opt for automobile engineering.
For mechanical, Galgotias University is not good for placement. You should search about SRM, I think their placements are better for mechanical engineering.