Diploma

Both will take 2 years each. Pursue PGDM through distance then you can do both at same time.

Follow the link to know about the admission process:-
https://www.shiksha.com/b-tech/course/b-e-lateral-entry-ssbt-s-college-of-engineering-and-technology-jalgaon-204438.
Also visit: http://www.sscoetjalgaon.ac.in/Admissions/BE-SecondYear.asp.

You can get placement after Diploma also but I suggest you to do B.Tech and then apply for placement as you will be placed at higher post.

You can try taking admission at Institution level by management Kota. Have you applied for last CAP round. The last date of filling form was from 30 July to 3rd August. You try by management Kota. Hope this will help you a bit.
Good luck.

The duration of the second year full-time Diploma in electrical engineering is 3 years.
Hope this will help you.

Part-time classroom means school/college take 2 to 4 hours class in a day.
Or
They can take your class Saturday and Sunday or holidays.