You need to be comfortable with the offer you are putting together.As far as hiring a GC to do a bid to cover everything. 

I am able to lock in a rate of 3.75% with a couple pts, so my COC goes up to 10% and I am comfortable with that.  

My advise would be to focus on the sales side first and once you get comfortable and confident making money that way, then look to develop a management arm off of your sales business.

I also want to retire around age 50-55 comfortable, which I would define as 150k/year in a lower cost city, and the retirement plans aren't good until my 60s.That is my goal, nothing more or nothing less.About me:I'm a mid-30s single without kids working in the Pacific Northwest , making around 190k on a W2.To help you understand my mentality, When I moved here several years back, I did not buy a house which in the appreciation mindset was a mistake.  

Sorry to challenge your misconceptions (not really) but $30,000 a year per child is spent in Washington DC for a 17% competency in reading in public schools.

I believe it's up to you and your partner and whatever you both are most comfortable with and agree to.

The primary reason I was looking to do the rent by the room approach is that as far as personal space goes it's not a huge concern of mine to sacrifice some comfort for a year while I have to live at the residence.

Then you could go in without an agent if you feel comfortable however, you will rarely overpay with a buyer's agent but you have to find good ones and commit to them or they will leave you on the dust as time is their most valuable asset.

As @Pat L. rightly said, you have to get comfortable with debt to scale in real estate.

I'm getting hung up on part of the BRRRR strategy, can somebody explain it to me like I'm a small child?