1) for leave and license amount of monthly rent X11 PLUS (Deposit)=0.25 % are taken in to consideration to calculate stamp & registration charges.
2) On loan amount there is no such calculation of stamp and registration charges.
3) As per section 17 of Registration act the immovable property whose value is more than Rs. 100 if need to transfer by way of any instrument then it need to be registered. Non registered document is void in eyes of law.
There for leave and license must be registered only.
4) There is no such time limit fixed by law for such license. Hence it can be 11 month or 999 years. It depende upon the party mutually agreed on fix period and lock in period.
5) please find link http://www.edraft.in/non-judicial-e-stamp-paper to get format of leave and license. Please do modify it as per ur requirement. I am attaching sample document for ur refference.