Welcome aboard, Malibumike.
This project sounds like a perfect fit for an
I-Pac from Ultimarc.

Programming utility can be downloaded
here.
You could program the IPac inputs like this:
1SW1 = Ctrl (default--already programmed)
1SW2 = Z
1SW3 = Ctrl
1SW4 = J
1SW5 = Ctrl
1SW6 = K
1SW7 = Space Bar
1SW8 = Ctrl
1Strt = P
Jumper input 1SW1=>1SW2, 1SW3=>1SW4, 1SW5=>1SW6, and 1SW8=>1Strt with 4 pieces of wire -- don't worry, it won't hurt the inputs.
Connect inputs 1SW1, 1SW3, 1SW5, 1SW7, and 1SW8 to the 5 momentary pushbuttons like this diagram. (+2 switches)

When you press the first button, ground is applied to input 1SW1 and jumpered to input 1SW2, giving you a "Ctrl" and a "Z".
Ultimarc also has classic arcade-style 1 1/8"
pushbuttons in various colors.

You can easily drill the button holes using a 1 1/8" spade bit, hole saw or forstner bit.
Scott