JEE

No, you can't fill JEE form now.

Admission to the first year of undergraduate Programme leading to the B. Tech/B.E. Degree is primarily on the basis of the inter se merit of JEE through On-line Off-Campus counselling conducted by HSCS through NIC*.
Thereafter on the basis of marks secured of (10+)2 examinations from any recognized board. A limited number of seats as per the guidelines of Haryana State Counselling Society will be offered for the direct admission. The criteria for the admission will be decided by BOG from time to time.
So, you can be hopeful for your admission in B.Tech courses.

Sorry dear but you have to score atleast 75% in each. But you can always go for the improvement exam. All the best.

As you are fronm Telangana you can get EEE branch in NIT Warangal. Yet you have second attempt and advance too you can get much more than this all the best.

I don't think reapplication will start for second attempt yet. You can still mail them your issue or contact them by the phone number available on their website in contact us section and test your luck.

Yes, they will accept JEE Mains score.

Yes, for JEE, the minimum percentage required is 50%.

It is both entrance and merit based.

No, it's not important to give both the exams but you should give it for enhancing your score.