Help me find a pin (on 80p Hirose) to signal when the FMU outputs are pilot controlled

I have need to use a couple of FMU outputs as safety switches. Let’s say one is a power-down, the other is a payload release. Neither signal may go “high” from vehicle power-up until I decide to press the buttons. The FMU signals all start “high” at Cube power on, and after boot few seconds later they reach their pilot controlled state and are ready to be commanded.

I want to change the least amount of things in software. Is there an easy way to find a “ready” signal among the other 79 pins on the cube header? I tried using nVDD_5V_PERIPH_EN, but that is controlled by a different thread and goes low 300ms before the FMU outputs reach pilot control.

Could I use another FMU output, and make sure it boots first, then insert a little delay after it? Are there some other pins I could set as a GPIO and set them low right after the FMU outputs are ready?