"either keep this place clean or all of you are getting 30 days notice.

They carry forward indefinitely until you have passive income to offset or you dispose of the 'activity' (i.e. the property).If you're below $150k in AGI, you may be able to use some or all of the tax loss from the rental to offset other taxable income if you can substantiate active participation."

Or all but one (you are living in it)?  

With regards to the seller financing for either part or all of the funds source... how do you stipulate pre-payment / early payment of the loan?

Just pick one, and get started.As you grow your experience, network, and wealth, you could go in any or all of these directions.

I hadn't thought about things like exit strategies or tenants rights or all that stuff (which was naive).

You can buy a property and take over the financing and then sell it for more using what is called a "Wrap" in some parts of the country or "all inclusive deed of trust" in some areas and "owner financing" in other parts of the country.

The claims sound good until you ask them specifics and learn they aren't accounting for their time, the cost of furnishing, taxes (if they are even paying them), or all the codes they're violating.

Oral agreements won't hold up in court.

As an example, an FHA buyer needing closing cost help has no chance of covering the difference between contract price and appraiser price, so if I’m the sellers realtor I’m telling my sellers there is no way this buyer can make up the difference should appraisal come in low.Whereas a cash buyer or a conventional buyer who is asking for zero help with closing costs and putting 10-20% down (or all cash) is in a position where they could afford to cover the difference between contract price and appraisal price.