Our spending habits have not really changed. 

Scott, our experience with them is that you have to go down in person and spend the majority of the day down there in order to get questions answered. 

Instead of looking for something to assist in real estate investing concentrate on what you are interest it and prepared to make a career of.

I know we want to leave room for an emergency budget, which is why I’m looking into leveraging an FHA/203k loan to assist with the renovations.

For drawings, what's the ballpark I should expect to spend for changing my garage into an ADU? 

As a Realtor, I pay almost nothing in fees to my brokerage compared to everyone else I have talked with, but my brokerage is not a big brand, I don't have a built in-assistant/transaction coordinator, there is no training program except the school of Hard Knocks, and most of my marketing I have created myself.

The original idea was to house-hack using an FHA loan in addition to a down payment assistance program offered in my area.

I would have to spend roughly 5k to get it ready to rent after that and then would refinance it to a conventional 30 year mortgage with 20% down.

I would recommend you make the offer YOU are comfortable making, and instruct your agent to add an escalation clause up to an amount YOU are comfortable spending, including higher than asking price.  

Also, joined Roofstock family, as well as Homeunion, and I was convinced that SF homes would be the best option, but after spending some time on your forum, I think multiplex units are better for a first timer like myself.