A relieving letter from employer is NOC from him for the employee to join any other employer. Such document is sufficient proof of satisfactory termination for new employee from ex-employer. No further document  is required for continuation of service from ex-employer to new employer.  

By all means  documents are more than sufficient for the said purpose. 

Your relation with ex is cut off. You cannot reach out anybody and seek NOC. They will not respond, relieving letter is everything.

If your resignation is recognised as technical resignation and if you are eligible for the benefits during the probation period then you can apply for it.

NOC is not a concern for this, it will depend on the eligibility alone.

Since you have shifted to another central university it can be deemed as technical resignation provided you ar3 eligible for the benefits during the probation period. 

Generally the technical resignation and the benefits thereon is provided only for the permanent employees and the probationers are not considered as eligible for the benefits of technical resignation though the resignation is accepted by the organisation during the probationary period. 

The relieving letter, the last pay drawn certificate as well as the experience certificate are just documents to prove that you have resigned the previous employment properly but they are not the documents which would make you entitled to the benefits of technical resignation.

You may clarify if you were a permanent employee at the time of resignation which would make you eligible for the benefits of technical resignation.

Yes is the answer for both of your queries

Your status as on the date of resignation is 'probationer', hence you may not be termed as 'permanent' employee.

Until and unless your previous employer is declaring you as a permanent employee you will be treated as probationer only.

1. On payroll of the employer you successfully completed probation.
2. After probation but before confirmation you resigned.
3. Your resignation is regular.
4. You are entitled to privilege of pay protection and service link with relieving.

You have not applied through proper channels .it is not regarded as technical resignation 

2)As per the Minis sv of Finance OM No. 3379-E.III (B)/65 dated the 17 thJune, 1965, the resignation is seated as a technical formality where a Government servant has applied through proper channel for a post in the same or some other Department, and is on selection, required to resign the previous post for administrative reasons. The resignation will be treated as technical resignation if these conditions are met, even if the Government servant has not mentioned the word "Technical" while submitting his resignation. The benefit of past service, if otherwise admissible under rules, may be given in such cases. Resignation in other cases including where competent authority has not allowed the Government servant to forward the application through proper channel will not be treated as a technical resignation and benefit of past service will not be admissible. Also, no question of benefit of a resignation being treated as a technical resignation arises in case of it being from a post held on ad hoc basis.

Documents are not sufficient enough for pay protection 

you have not applied for NOC but resigned from your job 

You are not entitled to pay protection 

The above documents are enough in your case

Dear client,  The simple answer to this question is yes.

If your resignation has been accepted and you issued with a relieving letter and other documents, your rights are protected, and your ex-employer cannot fault you for not seeking an NOC earlier anymore.