It sounds like a very promising candidate for us.  

If the seller/tenant doesn't leave the keys, we'll just open the door and switch out all the locks (which we always do anyways- The Mr is also a locksmith).We do see progress on the seller/tenant's move out, so that's promising.

A key, though, is when they promise you rates and terms ask them to produce examples of similar properties that they have closed on recently. 

However, I can promise you that real estate is not going anywhere.

And, although many try it and some will get away with it, I promise Orange County does not allow STR.

Quote from @Greg Scott: False EvidenceAppearing RealAre we referring to those that prey on people for short term gain over-promising and underdelivering? 

You could, with a fair deal, i.e. 60-90 days after purchase setting move-out dates for tenants that don't want to pay the new rent, then do a renovation, which is probably necessary, and subsequently, lease at market rates.That will also allow you to improve the value of the property.I have been offered deals where the current owner made promises to tenants (with and without lease agreements).

No issue, you're fine, you fulfilled your owner occupancy promise and didn't commit fraud. 

They're not scary, I promise.

When we were inspecting the place, there was evidence that the tenants received a similar notice in January and he never showed up.He promised us in late January that he would get us the leases, which my agent and I reiterated again multiple times last week during the inspection "Yeah, I have them on my desk in the office".