Still not signed sealed and delivered.

Should Tenant neglect or fail to perform and observe any of the terms of this Lease, Owner/Owner’s Broker shall give Tenant written notice of the breach, delivered to Tenant personally or mailed by certified mail, requiring the Tenant to immediately remedy the breach or vacate the Premises on or before a date at least fifteen (15) days after date of the notice (except in the event the breach is for failure to pay rent in which case the five (5) day statutory notice shall apply).

You might want to do a certified letter via post office wherein they have to sign for it, or hand deliver a letter wherein they sign a copy that you keep. 

About a year ago I was looking for the same thing and I found about 2 or 3 scammers.There was a guy claiming to work for PennyMac but he was using a Gmail account.Another guy sent me a picture of his Driver license, he looked white in the picture but on the phone he sounded Indian.If something smells fishy stay away from those guys.

@Cassidy BurnsAs others have mentioned, the numbers looks good, but on the other hand the market should be a main driver of your decision making to deploy your capital or investors.

I am getting new fridges delivered for $325 and new ovens for $230, water heaters $250, Arcadia white shaker cabinets for $110 a box...nice LVP flooring for $1.00 a sq foot...just an example

However, demand for housing in the city remains strong, delivering a 5% increase in the median sales price of single-family homes to $374,900.

They delivered on budget and on time.

This is generally accepted as Prima Facie evidence the Notice was  delivered, regardless of whether the tenant received the Notice or not. 

@Horacio GutierrezYou can always ask for the property to be delivered empty at close.