I increased my Heloc on my primary.

I double checked and these layouts do have two exit doors for both primary and the next gen suite as well.

There's a few different ways to focus on a lower rate such as with house hacking and making the investment your primary residence, requesting a significant closing credit from the sellers for standard rate buy-downs (which I've had great success with recently), or utilizing lenders who offer short term rate lowering solutions such as 2-1 rate buy downs (again, ideally paid for by the sellers).

It would be his primary residence so most likely a duplex or triplex house hack. 

It supplies fuel to the east coast of the United States. 

Depending on comfort and cash, it might be a viable option as you can build equity and then sell without having capital gains, assuming it's your primary residence and you've lived there for 2 years.

Quote from @Guillermo Perez: Can someone please let me know if this is ok for my first BRRRR.I got a $200k HELOC on my primary residence to help fund my first BRRRR.

I talked to my lender contact and, as Kerry mentioned above, it's pretty uncommon that a traditional lender would offer a HELOC product on an investment property (non-primary home). 

An ADU is a secondary dwelling unit located on the same lot as a primary residence.

out of state is more difficult than advertised. do you already own a primary residence?