I would imagine you would be able to profit several times the dollar amount with about the same amount of work especially if you are hiring out all or most of the work.

So option 2 seller get the same amount into pocket and buyer pay a little bit less.

But, if the existing tenants are a problem, then raising rents a sizable amount can be one way of encouraging them to move on.

Add replacing or fixing a toilet, lawn care, sometimes even insurance and it seems to be most costs would be a higher percent the lower the rental amount. 

I am ready to get my first rental property (already got pre-approval), and I also have 2 properties that I want to offer on (I did a fair amount of research on them).

Could someone provide examples of what mild vs extreme due diligence would look like with a 4 unit house that requires a moderate amount of TLC from the landscaping to the plumbing and electrical?

Please tag me what you need money amount for how long what the arv is and the amount of rehab and the cost of the property.

Under current market conditions in that price range for most parts of the country there is a huge amount of competition for distressed properties sub $100k. 

Even from the sharply limited amount of information given here, it sounds way, way, way out a hands-off investor's comfort zone.

Unlike single family homes, if you increase the NOI on an apartment building, you have instantly increased the value of the building by a nearly exponential amount (exactly how much depends on the going cap rate for the area).