@Derrick Locke I have a list of lenders that I use.

I was planning to refinance into another conventional mortgage from my current duplex to lock into the low rates, and also pull cash out to pay off the rehab that I did in the duplex. 

You should change the locks.

The L2O will lock me in though, wont it?

You never know when you need a set of ears to bounce something off of, or maybe a partner or JV. 

There's no one right answer to this, but if I were in your shoes I'd probably put a conventional mortgage on it now to lock in long-term financing at historically low rates, and use the cash to purchase more.Nothing wrong with a HELOC, but it will be at a lower loan-to-value ratio.

I use a wifi connected door lock and I send it personal door codes for each renter that activates and deactivates according to their arrival and departure dates.Maintenance contacts?  

For example the types of locks you have on exterior doors (California requires deadbolts on exterior doors to rentals.) 

. $150 for the door (Home Depot) $30 1 gallon of green paint $40 hardware (knob / lock / etc)$300 to cut the door to size (non standard) , paint , install

Some are rate locked, have extensions built in and are lower than typical bridge.