Legal Question in Landlord & Tenant Law in California

I do not understand what you mean by a new term in July. If the old written contract has expired, then they are on a month to month tenancy and absent rent control laws in your area you can give them a 30 day notice at any time that you are not going to renew the month to month tenancy [60 days if they have lived there for a year or more]. You must also read a Nolo Press or similar book(s) on what your and the tenant rights are or you will lose a great deal of money by failing to exercise your rights and breaking the law so they can sue you or move out. You are in a business now so you must treat it that way. Did you get from the former owners the security deposit put up by the tenants, because they can collect that from you and do not have t ask the former owner for it. Are you sure the prior lease says what you want it to and not not have any invalid terms? I use a much longer, more detailed contract/lease then the real estate agents form one which does not cover everything.

You cannot do anything. They have a right to stand by their original leases with the owner at the time they rented the property, but you also acquired all the previous owners rights under the lease at the same time. So until their current leases run out in July there really isn't any reason to do anything anyway.