Civil Engineering

Though it is entirely your choice. But, the best option for you is doing AMIE. It is the best option for working aspirants after passing Diploma.
Follow this link: http://www.amiestudycircle.com
About AMIE: http://www.amiestudycircle.com/about-amie.html.

Hello Priyanshu, Fire and safety is a must in every industry. In fact all industries have to employ trained personnel for this job. Hence I feel that there are enough opportunities for employment after you do this course.

Toughness of a course mostly depends on the aptitude of the candidate and their ability to read and understand a course better than the other. It is mostly a state of mind. Diploma in architecture is as tough, if not tougher than its counter part (Diploma in Civil engineering). Architecture is of 5-5.5 years duration wheres a B.Tech in civil engineering is of 4 years duration.
You should pursue a course which you feel comfortable doing/studying, and where your interest lie. Regards.

I'm not very sure of it. You can check the website or contact them.

Mentioned below are the software that are really helpful for civil engineers:
Microsoft Suite-Word, PowerPoint and Excel. You need these tools to compose documents, presentations, calculations etc.
Autodesk Civil 3D. This is your core tool for sites, roads etc. Learn it well.
Autodesk Revit. Information modeling of structure components. Plays nice with civil 3D
Autodesk Dynamo. Computational Design of Structures
Telka. 3D Modeling for Structures
STAAD for calculations
Python for coding calculations
Generally know how to create a cost estimate and schedule with Microsoft excel or Microsoft project. Or, with special tools like Sage or Synchro.