Depreciation on leased/leasehold property or office unit

There is an office unit at a commercial building under lease for 60 years with an option to renew at the end of the lease expiry. The lessor only charges maintenance fees and minimal ground rent from the lessee. An individual having a proprietorship business intends to buy the office under lease for using it as office space. Now, approximate value of transaction including registry, stamp duty, lawyer and other fees is Rs. 60 lacs. Here are the questions -

1. Under which block of assets class office unit/space comes in depreciation table as per Income Tax regardless of it being a leasehold or freehold?
2. Can depreciation be claimed over leased property when the property is taken under name of the individual with the intention to use it for his business? How will the accounting entry be done in both the books of the individual and proprietorship business if that is the case?
3. Can depreciation be claimed over leased property if the property is taken under the name of the proprietorship business?
4. Is depreciation allowed in general for leased property?
5. Can depreciation be claimed on furnishing the office like making renovations, adding furniture, etc.?

Note - The lessee makes payment of property tax, in fact the property has to be mutated with the name of the lessee after possession.