Ok well I didn’t know, but the RAP Pro Haybabusa for XBone doesn’t have a ‘front’ panel as the front panel got moved to the side, so its now a side panel. What I mean is, if it’s common ground, you can usually wire the buttons there to functions on the Brook UFB, like the Xbox guide button, Turbo (this button is often re-wired as the touchpad key for PS4 mode, as how many fighting game players or tournament players use turbo?), L3/R3, and so on. Panels that are common ground and have direct pinouts can usually be hooked up to the Brook UFB directly with either soldering or Jumper blocks or crimps. Some panels are not common ground and have their own circuitry; these cause problems unless an intermediate card is used between the UFB and the front/side panel. The most popular example of this is the Hori VLX “kit”, which is used to hook the Brook to the Hori VLX’s front panel.
I have absolutely no idea about your panel you are using. You should ask Darksakul or vicko or one of the other experienced modders; I’m a noob.