God invented Shields for a reason.
You plug a Shield into a Uno, Leo, Mega, Due, Nucleo, ...
All the signals connect correctly. You have a reliable mechanical combination too !
Why do you want to re-assign LCD_D1 signal ?
It means that you have to cut pins from the display shield.
If you have a valid reason, I will write the appropriate SPECIAL for you. This goes into the "mcufriend_special.h" file and not the "mcufriend_shield.h" (which is intended for plug-in shields)
David.