I am currently looking into a 7-unit apartment building on RedFin.Location: Chicago IL, North Lawndale, low income, high crime neighborhood.Asking price: 450,000Total monthly rent income: 7162Well maintained (so claimed)What should I expect the monthly average combined costs for [ vacancy + maintenance + eviction ] ? 

LLC is the easiest to form and maintain.

You need to look at property rights, adverse possession, easement by prescription laws as since the fence has been there that long and she and previous owner  have been maintaining that property for as long as they have,  they may already have rights to it, just need to declare it legally before the neighbor does anything. 

A more effective method is to read and attend various networking events. 

IMO, not worth dealing with used appliances - all savings will go out the window with the first repair call. unless of course your lease agreements explicitly require tenant to maintain appliances (not typical in CA but common in mid-West)Personally, I always buy new from HD and always get 5 year pro warranty - covers all repairs and in a few cases ended up with new units when they could not fix old ones.

I believe I need to get pre-qualified once more now that my financial situation has changed, so I'd like to ask all of you - How do you find and effectively vet mortgage brokers in your area?

If it was possible to do a targeted mail campaign directed to a potential Seller you know something about, even general demographics, that might have a special effect. 

Maintain less that 5% of company assets in nonqualified financial property 4.

I would like to know some good books or effective ways of educating yourself without going to the gurus.

I know one do = maintain a limit before you begin bidding and don't = change your bid maximum so you can stay focus and remove any emotion.