I understand structural components, city code, foundations, going rate for trim, paint, drywall, roofs... you name it. :-) just haven’t been on here in a while, due to working.

Other than that, it will depend largely on the timing and merits of the specific opportunities you have to choose from.

The podcasts suggest giving the owner financing options to choose from instead of just a yes or no type of deal.

With turnover, there is cost - finding a new tenant, lost rental income, making the unit rent ready (paint, repairs, etc).

So they went ahead and put up the sheet rock walls and tile, paint and finished the bathrooms. 

He seems a little desperate and kinda bugging me with over friendliness which I imagine is because of his physical challenges, I'm guessing but he seems friendly and skilled enough and we'd be working together replacing doors and refinishing/painting that formica covered composite wood stuff the boxes are made of and replacing the (horizontal) particle board.

Crowd Street probably has the most volume and deals to choose from. 

Thanks @Jerel Ehlert, o.k,. my implication if i purchase a property and assign/ sell it to an investor on a property that has back taxes owed on it, but has not yet gone to auction, it would be a good idea to disclose that, so that he can opt to pay them or not, or would i be responsible to pay them (if i choose), if i opt to purchase from a seller who owes? 

I don't see much downside to it other than the fact that the property tends to be noisier and you will have to deal with problems at random hours of the day which might affect your normal living situation.This can of course be minimalized by screening your tenants properly and choosing who will share a property with you.The upside is that you will live for much cheaper than paying rent or paying a mortgage by yourself.

It has no bering for the tenant in choosing to voluntarily leave or be evicted.