RootsChat.Com

Have you investigated Patrick Guttery?  ie to find out when he came and his forebears?

it was common in those days for other family members  or village families to sponsor other members.

Sometimes also looking at early time census records from the communities that people went to can provide information as many families/villages had chain migration going on.   

Is Bridget Fahy related to Catherine Fahy?

That is an Ancestry link and not viewable for those without an Ancestry sub. 

I am not sure why you are saying the parents would be Terence William Guthrie and Bridget. If the Australian family followed the Irish naming patterns the first son would be named for the husband's father and if the first son is James wouldn't that mean the father of Terence was James?

Can you pl provide a link to the passenger list.

 I can see two sailings for this clipper ship in 1861 on one listing (March & December), and on another just one listing  (March 1861) showing that the  ship seems to have been quarantined at Melbourne because of small pox on board. 

Where did the passenger leave from and where did he land in Aus please?

Link about this clipper ship
https://en.wikipedia.org/wiki/Donald_McKay_(clipper)

John Grenham has useful info about the name Guthrie and variations in ireland
https://www.johngrenham.com/findasurname.php?surname=guthrie

The three names from Tipperary came from Ardfinnan
https://www.johngrenham.com/c_parish/c_parish.php?county=Tipperary&surname=guthrie

These three names are on Griffiths 1852 (Tipperary south riding) are Thomas, William and Richard
From Ardfinnan


When you look at the 1901 census the oldest Guthrie there is only 45 so there may have been emigration. 
https://www.census.nationalarchives.ie/pages/1901/Tipperary/Tullaghmelan/Ardfinnan____Pt__of_Spitalland_/1707563/

The census also throws up another couple of localities that might be useful and that is Tullaghmelan
https://www.townlands.ie/tipperary/tullaghmelan1/

and another
Spitalland
https://www.townlands.ie/tipperary/clanwilliam/tipperary/spitalland/

Ardfinnan
https://www.townlands.ie/tipperary/ardfinnan1/

On Irish Genealogy there is a 96 year old Felix dying in 1891 so born ca 1795. 

https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1891/06075/4732548.pdf

Looks like it was registered by Anne Mckernan

From my understanding, by picking out words that are similar from the Latin (used in RC church) the comments are about a dispensation being given for two people to marry who may be related to each other in some way.

Consanguity - of the blood
Consanguinity (from Latin consanguinitas 'blood relationship') is the characteristic of having a kinship with a relative who is descended from a common ancestor.

Then you have a table showing showing who might be in these definition - that is called a degree. So we have degrees of consanuinity. In these case a special dispensation may have to be sought and depending on how close the relationship the person who could could give a dispensation  in the RC church who could give give rises accordingly.
 
https://www.uab.edu/humanresources/home/images/M_images/Relations/PDFS/FAMILY%20MEMBER%20CHART.pdf

King Henry V111 had several 'skirmishes' over marriage and permission from the Pope was denied thus triggering the schism.

Now from what I see
a dispensation was given
for a relationship to the 4 degree (superscript O) for one
and to the 3rd degree for the other.

A third degree kinship relationship is a first cousin, great-grandparent, great-aunt, great-uncle, great-niece, great-nephew, great-grandchild, half-aunt, or half-uncle.

A fourth degree kinship relationship is a brother, sister, uncle, aunt, first cousin, grandparent, great grandparent, great aunt, great uncle, great-great grandparent, niece, nephew, grandniece, grandnephew, or a stepparent.

I cannot read the handwriting but others will be able to.