Lease contract question

[Joe Xie]

I am buying a rental property at Bay Area with rental control has a tenant who is on month to month lease with selling landlord. I am planing continue with the term's the selling landlord. This is my first time to get a property with tenant, not to mention in rental control area so I come here for advice on following questions: 1. Do I need write a new lease or just a rent estoppel certificate refer to the old lease the tenant with the seller? 2. If I need a new lease, my agent suggested I refer to the old lease. But how do I refer to the old lease (I plan to honor all old lease teams ) in new lease? I plan to use exactly same write up as old lease, but then where and how I can refer the old lease? 3. Escrow will be close early next month, should I put 7/1 as start of new lease or 1/8? Or the date of the escrow close?