Is this correct ?
The button left is for making the LEDs run from left to right ?
The button tight for the opposite direction ?
And when one sequence runs, the output of the other one is supposed to be invisible ?
I get the feeling that the XORgates are not right for this job,
I’m afraid that is too difficult to realise with separate bits.
Do you have the LittleBits arduino W6 and 5 protobits W9 ?
If so, that’s all you need (with 8 long led bits) to make your circuit work.
I can always write your arduino sketch if you’d like.