However, I would like to set up an LLC so that I can start a business bank account to separate all revenue (monthly rent) and expenses (renovations, utilities, etc) from personal expenses. 

I know the 15yr rates are better, but the interest difference seems a small price to pay to gain a few hundred dollars or so per month of spending power.I too like the approach of using a HELOC on my primary, rather than a cashout, as the bill is separated off, as I don’t pay for money I’m not using, and as the LTV can be above 80%.

I plan to have a separate SMLLC for my wholesale business.

Basement has a huge 1 bedroom with closet space, full kitchen, full bathroom and also had separate entrance.

Basement has a huge 1 bedroom with closet space, full kitchen, full bathroom and also had separate entrance.

And plumbing subs are commonly billed separately.

These number include all utilities so you’ll need to adjust them down $100 or so if tenants pay separate utilities and of course take them with a grain of salt and run real comps when your looking to put in an offer.

(from the original deed recorded June 3 1998)  all these address's at some point were separate according to the deed and all had their own OPA #s. but somewhere along the timeline all above mentioned addresses were consolidated into one OPA # which is 836 n 6th st.So I have an AOS to buy 839-41 n Oriana street and the other buyer has AOS to buy 836-38 n 6th.

Is it possible to rent out the ADU and the main house as separate units? 

Separate meter, separate address from the triplex.The gray area is whether the Fannie Mae appraisal will be approved.