I've posted extensively about coastal Oregon vacation rentals and their challenges and production potential, typically a strong STR will generate roughly 10% of valuation in gross annual income. 

Tankless are a PITA.Tankless require descaling up to annually depending on water and if you fail to descale as needed the warranty is not enforceable.  

On my long time STR, occupancy (70%) and income is down.  

Diversity the way your income is taxed. 

Also maybe turning it into a two family home to maximize rental income is an idea.  

If someone is making millions to tens of millions a year in income WHY are they going to spend 50 hours with a new person that knows nothing in the field for 10k?

I think you may have very well narrowed down my strategy choices down to one of three; the BRRRR method (although this might be too much to start with for a newbie), the live-in flip that you mentioned (probably the most practical as I've been part of many different projects in the construction industry), and a combination of house-hacking/live-in flip (probably the most rewarding with a potential to swap between units as I finish one in order to bring better rental income).

Right now the rental income covers most costs and I’m going to be paying 600 a month of my own money. 

So correct me if I am wrong but doesn't an increase in rents decrease the cap rate since the property is more stable with a wider spread between gross income and the operating expenses

Following is the income for all the unitsRentsNew Rents Expenses Unit 1: 1800 sqft $ 975.00 $ 1600Insurance $ 6,000.00 Unit 2: 1100 sqft $ 900.00 $ 1100Taxes $ 2,728.00 Unit 3:  1100 sqft $ 925.00 $ 1050Sewer Charges $ 4,800.00 Unit 4(Apartment): 700 sqft $ 700.00 $ 850Vacancy $ 4,000.00 Total $ 3,600.00 $ 4,600.00 Repairs $ 2,000.00 Yearly Revenue $ 43,200.00 $ 55,200.00 Total $ 19,528.00 Mortgage Interest Only/m$1,460.00$1,460.00Mortgage Interest Only/y$17,520.00$17,520.00Current Income Projected Income Net Operating In $ 23,672.00 $ 35,672.00 Cap Rate4.30%6.49%Cash Flow With Int Only $ 6,152.00 $ 18,152.00 Cash invested $200,000.00$200,000.00COC3.08%9.08%What are your thoughts on this deal?