911, It used to be for all states except the fine state of South Australia!
I would be surprised if Townsville has signed him without looking at the fine points, such as availability......
Providing Leon Henry hasn't done anything stupid like be found lurking the streets of New Zealand at 2 am "going for smokes", then a smart lawyer should be able to argue to the courts to get the home detention conditions altered for work purposes.
As far as entry to Australia, check out these websites:
https://www.immi.gov.au/media/fact-sheets/17nz.htm
https://www.immi.gov.au/allforms/travel-documents/new-zealand.htm
It would seem that Leon Henry could potentially be a "behaviour concern non-citizen (BCNC)", however, "Circumstances where a person may be assessed as a BCNC include, but are not limited to, when the person has been: convicted of one or more crimes that have resulted in sentences of imprisonment that add up to at least one year"
The argument is whether home detention is deemed to be imprisonment, which may be a mute point if it is only 4 months, and therefore less than one year. Unless he has shared a cell with Jake Heke at Paremoremo Prison for other offences, then he may be OK to play for Townsville providing he is granted permission to leave the land of the long white cloud.