Buy a two-family house and rent it out - How to structure the financing?

If the bank cooperates, I might consider a 1% repayment financing with a proper option for special repayments. That way, you would definitely be on the safe side if the rental income fails. Then at least you can cover the installments.

Addition: And with the rental income, you then make regular extra repayments. This way, you remain as flexible as possible!

It would also be worth considering how financing should be handled from a tax perspective. Perhaps consult a tax advisor for that.