I'm working on my first diy project which is a F1 wheel with some leds, 7 segments screens, led matrix, buttons and so.

The problem is: I am using a Arduino Pro Micro, that will sit insde the wheel, and I need more IO than it provides me. Is it possible for me to use a CD74HC4067 for multiplexing digital buttons? With this CI's pinout I may use 5 pins for 16 buttons, instead of 6 pins for 9 buttons. 

Is there any special thing I should do alongside declaring the multiplexer properties on the sketch?

I've superficial knowledge on programming, so if anyone more capable could help, I would be very grateful.

PS:

Also, I've read about desoldering the ProMicro tx/rx led indicator resistors for two more pins (B0 and D5), has anyone already done that? Could I just do it and add those two pins to the button matrix on the SimHub Arduino Configurator, then just set the pins on the sketch manually?