Engineering

It depends on your course what kind of course do you want pursue.

Yes, you can get admission in AMU for B.Tech, and also you'll get lateral entry mean direct admission in second year, but you have to crack the entrance exam.

Yes, you can get admission in IGNOU for pursuing BA via distance mode of education after Polytechnic in electrical engineering.

It is all about your interest. But, it is better, you should choose BCA MCA from PES University rather than doing B.Tech from an average colleges.
B.Tech will be better, only if you got good government colleges, otherwise you'll only spend without any good reward.
Your average placement will be aroun

No, with this rank you'll get Government College for lateral entry. For lateral entry in government colleges your rank should be around 100.

On the basis of your SC rank, there is 70% chance that you can get IET Lucknow, but surely you can get seat in:KNIT.
BIET
MJPRU
KIET

The faculty is good, pretty supporting, with detailed knowledge and they guide you towards a great direction with timely epiphany sessions.

Your chances of getting ECE are quite low. Try for some other good private colleges.

You can get any branch which you want. Congratulations on securing such good rank. You can check the list of colleges on shiksha.com.

I think it's better you should choose or lock a college taking into consideration the branch and college.