But with that being said, there is NO way to eliminate foot steps and heel sounds if the building is wood framed. 

This equates to more days that the unit will be rented, and it will also eliminate the leasing fee from the PM company every year (if the tenants stay more than one year).Everyone has a different opinion on this subject.  

@Taylor L.Actually you do not need a custodian with the Solo 401k plan, it is not required unlike with SD IRA. 401k plan/trust can be setup with account holder being the trustee/plan administrator thus eliminating a middle man (custodian) and all related fees that come with it, not to mention red tape, delays and inconvenience. 

Granted that hiring a management firm would probably eliminate any cashflow, I am leaning towards just managing it myself and assuming that since the place is in great shape, the day-day involvement would be minimal.

(Many jurisdictions did his 5-10 years ago to eliminate people arguing the value of their properties. 

You may need to refinance to eliminate PMI.Remember that your HELOC counts against your total LTV.

Should I refinance out of an FHA to eliminate PMI (which would save ~$500/month) or get a HELOC so I can use that capital to invest.

House hacking would have a number of benefits in your situation such as:* The ability to pickup multiple units on one shot with a lower down payment* You will lower or even eliminate that $2100/mo rent you are currently paying * You will gain valuable experience in property management without having to do it at a distanceIf you are going to continue to rent for the next few years, its a no brainer.

I personally did the comparison myself and for my situation (I got 2.25% on my FHA loan with ~82% LTV), my MIP won't need to be paid after the 11th year and I would come out ahead financially in all scenarios (in the beginning because I put less than 25% down, and in the end because my monthly payments would be lower for 19 out of 30 years due to the eliminated MIP after the 11th year).

(These days it’s pro-rated if a rental first it has NOT been eliminated. )As far as being too late for a 1031.