My end goal is to get another stream of income that will take me into a comfortable retirement.  

I'm not one of those people who constantly needs a cheerleader or encouragement... but I'm starting to think that this was a mistake.  

You have to get all the docs from the seller upfront because as time goes on they will get frustrated at the banks constant request for documentation and might give up on the whole thing.

Cap Rates really don't apply until you get into scenarios where there are multiple streams of income on a property.

The only reason it is structured as unsecured is if 1) the borrower's net worth is substantial and it's basically a credit card or 2) collateralize funds cannot be secured for a specific reason (such as high volume inventory purchase/sales) but the ave balance stays constant.

You can improve marketing, revenue streams, cut expenses just like any other property for the value add.

This tenant isn't doing anything illegal, but she constantly fights with other tenants, is always complaining and verbally abusive, and threatens to sue at the slightest rent increase. 

. $10,000 isn't very much in the way of a partial, definitely not enough for a full note (though I have seen some $16-18k notes recently), so the partial that you buy would have to come from someone who may have bought the note with intent to just keep it.As Bill mentioned, when you buy a partial, you're buying the front end payment stream.

I love my day job as a software engineer but want to have multiple revenue streams and rental properties look like a good opportunity for steady cashflow and long term wealth.

Yes, the headache will be there, but sounds like you'll have a team and if you can target 8-10 of these deals, you'll have a nice stream of income...