Lost Income- normally 18 to 24 months. 

FHA now allows us to count rental income from an ADU (additional dwelling unit) to help borrowers qualify.

The rates are high right now but these loans are limited based on cashflow so you cant take a loan that costs more than you're receiving in rental income.

Correct - Track all your income and expenses.The bookkeeping will determine whether you are profitable or not.it will also be good to compare from year to year your income / expenses to see what expenses you can potentially try to limit.I.E.

If you pay two years' worth of property taxes in 2025 (January and December), both payments are deductible on your 2025 return, potentially reducing your taxable rental income significantly.

I don't know your living situation but if your paying x,xxx for rent or a mortgage and instead by living in one side and renting out the other you will be paying y,yyy instead and y is less then x that's great, especially if you can rent out your primary residence and make income there too. 

Quote from @Polat Caglayan: How much do I need to invest for a house and a thousand dollar income?

Sometimes, there is also a tenant already in place which means you can start generating rental income from day one.

The problem is, that's not proper accounting because a credit card is a liability, and doing this workaround will reduce your assets rather than increase your liabilities, which totally messes up your balance sheet and debt-to-income ratios.  

It's early, but it looks like we'll earn around a 8-9% ROI.