Can you buy a rental (either single family home or duplex) where the rent will cover all of the expenses? 

If it is not zoned for multifamily and the city has no plans to update that subdivision, you may want to chalk this up to an educational expense.

IF they can win one in a bidding war, plus cover the appraisal gap on top of all of their other expenses.

When I'm analyzing a deal and accounting for future expenses, how much more do you think I should increase my repairs portion in my expenses for section 8?

.= approx. 700My monthly cost for living in one unit= approx $1800 (which is what I pay to rent right now).

You would need to document your hours along with the hours of anyone else.Do you plan to pay this 'co-host'.If you list that as an expense on the return it would likely turn as a flag in the event that you get audited.Best of luck.

Now, pair this strategy with the concept of house hacking, where you live in the property and rent out rooms to cover your mortgage expenses.

For example, with 25% down what are people getting after all expenses are paid? 

I live in Winston Salem, NC.

If you have 30 houses with a total of $3 million in equity, then you could split them into three separate LLCs with $1 million each.The more complicated you make it, the harder it is to keep straight and the more expensive it becomes.