I talked to a property manager my agent recommended.They are going to charge 1-month rent for lease fee when they land a tenant, and 10% rent or $100 minimum per month per unit; half month rent for lease renewal.They can indeed accommodate appliance delivery and manage small renovations, but that's going to be $60/hr.

How would you go about handling her exit in general with proper notices, delivery confirmation from post office on letter being delivered, etc?

Per my State, check you state and local laws.They need to provide a forwarding address to send them back any or all of their deposit.If they don't provide a forwarding address send them this letter and check if applicable to last know address, delivery confirmation or certified is a good idea.

DELIVERY OF NOTICES: Any giving of notice under this Lease or applicable New York law shall be made by Tenant in writing and delivered to the address noted above for the payment of rent, either by hand delivery or by mail.

There is no limitation on how much you can expense.1) The safe harbor applies to amounts paid during the tax year to acquire or produce what the regs call a “unit of property” (UOP), you must meet these requirements: (1) at the beginning of the tax year, the taxpayer has written accounting procedures treating as an expense for non-tax purposes amounts paid for property costing less than a specified dollar amount (which will be 2500 for you), or with an economic useful life of 12 months or less;.(2) the taxpayer treats the amount paid for the property as an expense on its books and records in accordance with its accounting procedures. ( do this on your bookkeeping software or whatever you utilize)(3) the amount paid for the UOP doesn't exceed $2,500. as substantiated by the invoice Note: The cost for the Unit of Property includes l additional costs (for example, delivery fees, installation services, or similar costs) if these additional costs are included on the same invoice with the tangible property.Eg:A purchases 100 printers at $500 each for a total cost of $500,000 as indicated by the invoice.

I have been listening to the podcast daily for the past few months during my dayjob as a delivery driver.

I read the post you are referring to, and undoubtedly, the post has some validity to it, that said, I just think the delivery could have been better. 

I know in particular they have partnered with Seamless food delivery and maybe even airbnb.

I would want the home owner to cover that cost with a delivery fee.

When you mean developer financing, is this financing for pre-construction properties (i.e. you put down a payment to hold the property during construction, then upon delivery you sign a mortgage and begin paying on the debt)?