Wonderful work! I do think you should use this as peace of mind - you can pursue what you want, and you have a fail safe. But you can't access a lot of your money without substantial lifestyle changes, like selling your or your rental house, so you need to be realistic about that.
Like Patrickza, I am also a bit conservative. In our circumstance, we only count our investable cash and liquid investments towards our FIRE number. If we rent our house in the future, we'd also include the monthly cashflow, but not the equity because we don't plan to sell in the short term where the money would benefit our stash. In your case, I'd include the retirement accounts, and the cashflow of the rental, but not the equity in either unless you plan to sell and move. So, you have [(260/25)+ (yearly rental income- expenses)= Passive Income Yearly Spend] and that is what I'd compare to your FI number.