First of all, you should be getting an estoppel certificate, signed by seller and tenant, that outlines current rent, current deposit (even if its $0), and any current outstanding oral agreements.

Here I simply outline my expectations for the tenant at move out. 

I've seen the laws, but it doesn't outline what happens for a situation after you've given the security deposit back.

I'm definitely using your letter outline to officially tell them about the transfer of ownership. 

I would make sure to outline who is considered a tenant and explain that no one else is allowed to move in without approval.  

For next time, definitely make sure to outline how you will handle service calls, etc. 

The US Environmental Protection Agency's mold guidelines outline when moving out is necessary depending on the size of the affected area, type of mold, the mold's effect on air quality etc.

We actually have all of our criteria listed in a document that outlines our entire application process - timing, fees, etc.

Just tell him exactly what you outlined in this post.

Landlord reserves the right to revoke consent given in this agreement via 7-day notice (as outlined in Paragraph 12 of the Lease Agreement).