Just pinning a few things in this thread so others don't have to cover the same ground.
In the NZ Births, Deaths, and Marriages Historical records there appears to only be one birth of a Thomas Mcguire in 1892:
1892/13945 McGUIRE Thomas Bridget Patrick
There are no Thomases for MAGUIRE in this same timeframe.
For the marriages of any 'Charles' McGuire between 1876 and 1893 there is:
1878/3001 Emily Annie Smith Joseph Charles McGUIRE
This latter couple had a child:
1879/11919 McGUIRE Mary Elizabeth Emily Annie Joseph Charles
There are no Charles MAGUIRE marriages.
This is the Immigration record relating to the Charles on the Orari
https://www.familysearch.org/ark:/61903/1:1:FS14-76LCharles is listed as 34 years with a birth date of 1842.
His passage was part of the Assisted Immigration/Emigration scheme.
Might the Charles you are seeking have exited NZ fairly promptly for Australia?
Does your Charles have a middle name?