Well...
The blue actually is purple on the Z3200 so that is expected. The yellow, on the other hand, should not be mustard. Although I have actually seen and tasted some poor quality mustards that are quite close to the correct yellow of the Z3200 (obviously artificially colored)
.
A lot can happen during one year of no use, specially if the printer was unplugged. Inks may have expired and separated on the carts and on the tubes/heads.
Before replacing the heads (that may be necessary) I would remove and agitate all carts for a few minutes, perform some (a lot) head cleanings to try to clean the heads and, at the same time, purge ink from the tubes.
Print several nozzle check patterns during the cleanings and see if there are any improvements.
Good luck.