For rent collection, sending an invoice on the 20th greatly helps with getting paid on the 1st. 

In exchange, I'm thinking that she would collect all the cash flow and potential equity until I refinance and get the loan originated in my name...

That is a fine approach and is more conservative.However, for my preferences, I would focus on optimizing debt for cash flow.

Key Points from the Article:Our very own @DavidMeyer, our housing market expert, and host of the BiggerPockets Real Estate Show believes home flipping and BRRRR are due for a comeback.Reasons for optimism:1.

IMO the optimal count is 10-12 for most 3/2. 

There appear to be some new startups offering to pay up to 50% of the down payment on a house in exchange for around 35% stake in the house (they collect this upon sale).

Agreed but if they sell a property, that’s less fees they’ll collect every year and you’d want to sell the worst property which would be a significant hit.

Is a PM allowed to share the tenants application including credit reports and other info that is collected during the application process?

While it’s true that getting a second conventional loan immediately can be challenging, especially if you’re looking to maintain optimal financing terms, it’s not impossible.

The average tenant is very difficult to collect from depending on your state's laws.