Well, okay, so I tried using the CD4067BE before, but that's around the same, so I'll just use the buttons by themselves again for trying to use the Arduino. Thanks for the help everyone. Oh, and also, the problem with that mux is that it would read one channel at a time, it wouldn't read multiple buttons like how I wanted it to. Again, thanks for all the help! If you want I can give credit to everyone who helped.
Okay, so you got me. I actually DON’T NEED it. I just want the diodes, just in case of multiple button presses. But, I am switching to the regular way of buttons, good ol ground and an input-resistor. It’s because @johnwasser makes a good point about the project needing an Arduino Mega anyway.