Dear Dr. Majumdar,
as regards (2), if situation demands, leave sanctioning authority sanctions such leave on the basis of two applications as you said. There should not be any constrain for that.
I have seen from my work experience, that many of the employees who have ‘deposited’ 300 Earned Leave in their Leave Account, takes leave with almost least important reason (mainly for the background reason that the extra 15 days E.L. will lapse in the next six months) by applying for leave maintaining the timeline making the leave counted as ‘authorized’ where as an employee taking leave with a short notice, or without being capable to give prior notice due to emergencies beyond the control of the employee like sudden serious illness of family member(s), such leave is counted as ‘unauthorized’ due to non-compliance with norms. Hence, there is nothing specifically mentioned in rules as regards ‘authorized’ and ‘unauthorized’ leave, I feel, the leave sanctioning authority in the local administration may be liberal towards judging the case.