Determine how much money would be needed to handle each risk, and determine if you have sufficient liquidity / cash flow to ensure you can “stay in the game”.This is of course in addition to all normal “due diligence”, financial forecasting, etc. 

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

Big enough that you aren't competing with newer investors/house hackers but small enough that you aren't competing with institutional money.

Strictly speaking from a financial point of view multi family's almost always make more sense unless your walking into some equity in a single family.

When you're on a temporary visa, especially without a clear path to permanent residency, the risk involved can be substantial—both financially and legally.

Mostly worried that even if I find a place and the money, that I'll be making a big financial mistake and have little left to cover unexpected costs.

Every local bank does dscr loans, 20yr term, with 3 or 5 yr rate reset, you might be able to get 25yr term but all will require personal guarantee to start and 3 yr historical financials.

Great tools that get updated regularly.I am on the lending side of things and would be happy to hop on a call with you anytime to discuss financial strategies and help answer any questions you may have about nearly any loan product available to help you on your journey, even if they are not products my capital partners offer.We are all here to help you learn and grow.

Which niche is better for financial freedom?

I look at the tenant's financial situation (income security) as a very important part of the property analysis.