What's more common if the condition of the place is terrible is to get a $100K-assessed place down to maybe $70K if you paid $50K of so for it.

It appears to be common for many of the buildings to be divided into many rooms boarding house style and you pay for a room w shared common area.

This is very common in Southern California, and developers have been pumping out new construction left & right to replace the current market that's filled with old, deteriorating buildings from the 1960s. 

HOA's usually only have control of the outside and the common grounds of the property. 

If you find someone that will "do it all for you" - turnkey - they're making significant money off the deal one way or another, commonly on the spread of the purchase and sale of the property.

There are much more to these stories, however, the common thread that I saw with both of them is that they didn't consult a mentor or coach in their strategies in acquiring these properties.  

Everything is negotiable and asking for closing cost help is very common in the first-time buyer market, at least in the Baltimore metro area.  

Not just emergency repairs, but also pro-active repairs like keeping track of the roof, exterior spaces like porches and decks, mechanical, common spaces and grounds. 

Is it common/easy to sell a lead to another investor?

The parcel owner’s liability for assessments may not be avoided by waiver or suspension of the use or enjoyment of any common area or by abandonment of the parcel upon which the assessments are made.I'm not an attorney and this is not legal advice.