Teacher

As UGC has granted one regular and one open/ distance, then logically should not have a problem.

This will depend on the field that you wish to pursue. ATD is a general course.

I think it is better to complete Ph.D after completing B.Sc and M.Sc because B.Tech enables technical knowledge rather than teachable and Ph.D provides research knowledge for you to teach the future generations.
Thank you.

One can become a lecturer in chemistry by doing B.Sc M.Sc and CSIR UGC net as the minimum qualification by UGC. Now lecturer is assistant professor job in higher institutes. PhD in chemistry will surely open new avenues for a teaching profession in this field. Scope is great one has to be consistent in his efforts. All the best. Salary in starting 60-70k in hand in a govt indtitution.

You should have a post graduate degree from recognised university and also good knowledge of subject you applying for.

To become a professor of physics, a research degree is must and especially a PhD degree in physics.

A minimum of 60% is required.

If you're much into English, then choose humanities or arts with English as both compulsory and optional subject in your intermediate, following which go for the Bachelor and Masters degree in English.
After that, do a B.Ed.

You can join as a lecturer in self-financing management colleges with your current qualifications. But if you are looking for government colleges, you should have to clear UGC-NET examination.