Pull down/pull up resistor for 5v input
Since your project will be interfaced with a keypad for a decoder, i think a 1/4 resistor would do just fine. This is because digital applications usually just play around the milliampere currents and with a rating of 0.25 watts(1/4) this even gives you an allowance. Just use the correct resistance, for this case you just have to avoid going below 100 ohms. You would commonly see 1W resistors for power supplies since it involves higher power ratings (higher voltage and current).

And yes no need to add VCC for the keypad; the C0, C1 and C2 pins are the ones supplying the voltages (this depends on your programming) for the keypad. :)