Actually more becuase now you are self-employed and have all of those pesky overhead costs. 

Sometimes large employers will rent furnished apartments for their employees coming to town on a regular basis.Also, if you believe strongly in the appreciation of the house, how bad would the negative cash flow be if you did long term rental? 

I've heard of folks using the equity in their rental properties to purchase additional properties and I'm trying to learn if this would make sense for me.

In addition, you can listen to the Straight Up Chicago Investor for great local knowledge and contacts. 

Additionally I spent $35,000 on property taxes, $17,000 on insurance, $35,000 maintenance and repairs.  

ADUs additions in single family zoned areas add less value than the hands off cost of the ADU addition.  

Do they charge any fees in addition to their asking price for properties?

In addition to the solid list from Joshua, Typically LLC costs.

What do you mean by the additional $18/sq design fee was not included? 

You have consider that your average first time home buyer, has no clue how to read an LE, does not even know what fees are for what, and needs that additional assistance for them to feel comfortable purchasing their first property.