., because I don't need all the extra services they provide; I just need an accounting service specifically for PM.

This "7 Day Sale" method sounds like you are depending upon "The Greater Fool Theory", and, "You make your money on the Sale". 

A cash out could very well be 50% to 70%, (or they may not do cash outs) depending on the lender so you'll need to ask and shop  around.Each property must be appraised and title insurance obtained on each, so you're not saving much in loan costs except they may close as one transaction, filing fees will be applied to  each property as well.

It just depends on your comfort level.

I'd also highly recommend getting an appraisal or at least having your real estate agent provide a BPO prior to negotiating with any "investors". 

Has anyone found a data provider that is more up-to-date?  

So depending on how good the numbers are and if seller accepts my clients aggressive offers play heavily into the strategy.

The new trend they started a couple years back of arbitrarily needing to raise the annual subscription fee $100 each year to "provide the best service" would fit into this also

It is due to the saturation in listings and low returns on Airbnb (depending on your IN price on when it was bought).

Depending on amount of capital raised, these costs may be de minimus, but they are real costs that are being incurred somewhere, and in a common syndication (or as Spark calls it "co-investment"), they typically are born by the investors (you).