The Holyoake/Marshall Government arrested people and put them in prison just so they couldn't vote in marginal seats. This happened in 1972 in Wellington Central when people could be jailed for protesting against compulsory military training, and the seat was narrowly won by National.
It took Martyn Finlay to bring some rights and real justice into the system (and of course Kirk got rid of CMT an lowered the voting age). Finlay's reforms were later overturned by another National Government. I see Andrew Little as a potential Finlay so I think Arthur Taylor will win this but maybe by legislation rather than through the court. None of your groups listed will be denied the vote.
Very interesting! Do you have any recommended readings on that topic?
I remember it as I was there at the time but I'm not sure whether any of this has been formally written up. There have been pieces written about Martyn Finlay as he was a long time Labour Party social justice activist and made a significant contribution to the Kirk Government's reforms.
I will need to look into this!