Question About Custom Fightstick Build

Hi Everyone. I'm new here so be gentle. :-)

I am looking into creating a custom built fight stick. However, I would also like to use it for twin stick shooters like Binding of Isaac. I am curious if a normal PCB board like Cthulu would allow me to wire both the "A/B/X/Y" buttons as well as a second joystick to the same terminals...

So the layout would be the same as a normal fight stick install on a Cthulu PCB board but with a 2nd joystick installed on the A/B/X/Y buttons.

Does anyone know if this would cause a conflict or would it just be a secondary way to activate those buttons?

Thanks in advance.