I am trying to get interest only loan to scale my portfolio and increase my cash flow.

My normal pattern has been to find rehab and rent properties for the cash flow.

In some cases, it may even generate positive cash flow, allowing you to save or invest the extra income.Build Wealth: Over time, the rental income from the basement apartment can contribute to your overall wealth-building strategy.

The properties all cash flow nicely and current interest rates range from 4.25-5.25%.

Cash flow is king in the BRRRR world. if they dont cash flow its going to be difficult to refinance and do it again.

The tool/template should cover (any other recommendation are appreciated):Cash flow analysisCap rateROI (Return on Investment)Rent rollExpenses and operating costsFinancing and amortization detailsDo you have any suggestions for resources or templates that would work well for this purpose?

Both cash flow extremely well

They usually don't cash flow, but a big part of your housing is subsidized by your tenant. 

I’ll run airdna projection and underwrite at current rates to see if cash flow positive.

I will not lose the forest (the fact that I would be buying a property that is deeply negative equity) for the trees (the fact that it might "Cash flow"). - I understand basic tax principles.