If you understand the lender's options when it comes to “taking over the house,” you’ll see why everyone here is correct when they say that lenders prefer to simply collect your points and interest.The cleanest way to obtain ownership is thru foreclosure.

I pay $300 realtor commission for new tenants.Otherwise 8% of collected rents. 

They issue me 1099 Misc's for all gross Rent collected.

If you aren't going to self manage this changes your cashflow by $138 (6%) to $230 (10%) of rent collected. 

However, I use Cozy for rent collection and it's free. 

Is it customary for the manager to get a percentage of this 10% or any other fees collected?

On the cover the POHs seem like a good way to collect rent but they also come with the normal maintenance, frozen pipes, etc issues of running a rental property. 

If I used the "Tenant Dashboard" to say they paid rent then it would add a rent received transaction into the bank transactions making it look like I double collected on rent.

They sell it to a new buyer for $20k down and collect the rest in payments.An example of sub2 with owner finance: An investor buys a house sub2. 

Don't rely on him paying and if he doesn't pay you, send the payment in anyway and try and collect from him.