It would be suggested to pursue Engineering Physics at IIT Bombay rather than Electrical Engineering at IIT Roorkee. 

When it comes to studying physics at IITB, there are some key differences between JEE physics and college-level physics. Here are some important points to keep in mind:

• In JEE physics, you study formula derivations after brief explanations of concepts and practice a lot of problems in that topic. College-level physics courses are typically more rigorous in theoretical and mathematical content, and problems are solved to help you understand the concepts more deeply.
• While EE does not have any pure physics courses after the first year, it focuses on making you an electrical engineer. Core courses include analog and digital electronics, signals and systems, network theory, electronic devices, microprocessors, power electronics, and some relevant math courses.
• EP, on the other hand, has core courses like quantum mechanics, electrodynamics, statistics, relativity, classical mechanics, waves and optics, nuclear physics, etc. There are also important math courses up to your second year.
• EP trains you in core physics concepts and prepares you for experimental physics and electronics, giving you many options for your career path. You can work in theoretical or experimental physics, electronics, statistics and stochastics, CS-related research, or pursue higher studies in physics.
• When choosing between IITB and IIT Roorkee, consider factors like the quality of professors, campus culture, and location. IITB has excellent professors, a beautiful campus, and great cultural and sports scenes, and is close to TIFR, which provides opportunities for collaboration.
• When it comes to placements, most EP students go for higher studies because they are passionate about physics. For EE, core and non-core jobs are similar to those for other courses in terms of job security and salary packages.

Finally, the "brand" of IITs, especially IIT Bombay, provides a sense of job security that can be reassuring for graduates.

I will restrict my answer to Engineering Physics and Chemicals only as I know the same only. 

• The major criterion followed at IIT Delhi by all the branches is a well-maintained CG. To secure good placements one has to constantly score a good CG throughout the program.
• During your admission, the department does not play any role but your 85 percent constraint on minimum possible strength does.
• Engineering Physics is a unique branch for those highly passionate about Physics and want to pursue higher studies in the same
• To secure core jobs, one has to move to MTech in Engineering Physics from BTech in Engineering Physics.
• For Chemical Engineering students, BTech is more than enough to secure decent packages and great research opportunities outside India.
• Consultancy and Analytics jobs are offered equally to students of all the departments 
• Engineering Physics graduates usually take up consultancy or IT jobs 
• Chemical Engineering is the most laid-back department of IIT Delhi with very flexible academics thus making it easy to maintain a decent CG throughout. 

I wouldn’t suggest anyone go for Engineering Physics if they have no intention of pursuing it later. Instead, look for other options in BTech and explore your interests.

Both BITS Pilani and IT Guwahati are reputable institutions with strong engineering programs. It’s highly recommended that you go through the contents of the curriculum once before opting for any major. Most students skip this and regret it later as they are forced to study courses they least expected. Go through the books of these courses and determine if the matter intrigues you or not. 

IIT Guwahati Engineering Physics program covers a wide spectrum of fields. Although the placement scenario is average, it definitely quenches your thirst for knowledge of Physics and also prepares you for higher studies. 

Another good option for core physics is MSc at Kanpur or Kharagpur. Although EP will expose you to multiple options, you will require another degree. It’s better to analyze your interests deeply before making the final decision.

As far as the EEE at BITS Pilani is concerned, I am strongly against anyone joining BITS irrespective of the branch they choose. The curriculum is poorly structured and lacks flexibility. The placement scenario is deteriorating day by day. The exposure offered is null and thus BITS Pilani should be your last option when all doors are closed. You will end up wasting your time and money with no solid knowledge up your sleeve by the end of 4 years.

Ultimately, the decision of which program to choose depends on your personal preferences and career goals.

IISc Bengaluru’s BS Program is still in its infancy but has great scope for development in the near future. In fact, I consider this program even better than the Engineering Physics offered at IIT Delhi. A few strong reasons support my stance on the same area:

• IISc program curriculum is very flexible and students are at the freedom to opt for any course of their choice provided that they have completed the first year m’s highly dynamic course. Whereas IIT Delhi's EG program has little flexibility as you will be studying physics-related courses throughout the program with little space to choose a different topic
• Globally, IISc is a well-reputed science institute, and its scientific research and teaching methodology are even better than IIT Delhi.
• The professors of IISc Bangalore are more experienced and learned than IIT Delhi and their unique pedagogy offers a great learning experience. These professors enjoy worldwide recognition and thus their recommendations are highly valued
• For someone who is interested in Academics more than jobs, IISc is a very good option. It holds the 35th position globally for providing jobs.

Despite being a new course, I will highly recommend you to go for it owing to the tremendous scope of development it has.

The choice of college and branch totally depends on your inclination and career prospects. Yet, a few pointers you might consider 

For MBA/ non-core jobs/Startups: IIT Delhi Textile is the best choice if you are looking for any 3 of these options. Its excellent location provides enough exposure to give you access to unimaginable opportunities. Many events hosted by industry experts, CEOs of big companies, and successful entrepreneurs will give a better insight into the startup culture. Moreover, students preparing for competing exams can easily access coaching centers nearby.

Research in Biotechnology: If you are interested in research in general or Biotechnology specifically, then the Biotechnology at KGP is an excellent choice. It is one of the most demanding fields in terms of research and general growth. With a good CGPA, you can find a research internship or you can apply for MS or Ph.D. Even job opportunities are plentiful. 

Campus: IIT Delhi is better because of its small size and location

Lastly, Engineering Physics from IIT Guwahati should be considered only if you are genuinely passionate about Physics and want to pursue a research career in the same. The curriculum comprises high-tech mathematical concepts and is a good option to pursue a career in economics and computer science.