ANCESTRY HELP

anybody out there who can help me with finding info on my elusive
ancestors.

James David CROWLEY  b.  1837, Kilrittain, Cork, Ireland
he emigrated to Australia in 1868 on "southern cross".
Married Catherine CAMERON in 1873 in Victoria.
He died 1900 Corowa, NSW, buried by an undertaker and 2
witnesses and i believe buried in an unmarked grave.
Death Certificate states he was 47, which is untrue.
His parents listed as David Crowley and Catherine
Mehegan.

QUESTION:  Where did the information on his death
certificate come from, who provided that?

What happened to his children, i guess they didn't see him
again after he deserted them in approximately 1888 or 1889.

James Duncan CROWLEY married to Ellen LAWLOR (my
grandparents), he grew up with Duncan and Flora Buchanan
CAMERON.

James Duncan CROWLEY was a devoted husband and family
man, who was kind, fair, loved his 46 grandchildren dearly,
a good story teller, great sense of humour.  He died on my
19th Birthday.

OTHER ANCESTOR:
Thomas LAWLOR and Catherine MURPHY, haven't been able
to find much out about them either.

I have heard not nice stories about my granny Ellen Lawlor CROWLEY,
but to me she was always lovely, i remember her with great fondness even
if i am unhappy about the way my mother was treated by her.  My
mother was shunned because she was not a Catholic, granny wouldn't
go to their wedding and never came to our house, even though it was
just a couple of miles away.  My late dad used to always say to me
"granny always loved you but hated your religion", she had special
rosary beads for me and everytime i went therei had to say Hail Mary with her.  Cousins tell me that granny used to say nasty things about her grandchildren to other grandchildren, i never experienced that so i cannot say.
 I remember going to her house a lot when i was growing up.
Sometimes she used to let me brush her longsilver hair.
I remember she always sat at the same place at the kitchen
table, wore dark clothing and always wore black lace-up boots.

I have a picture of Catherine CAMERON, have heard unsavoury
stories about her too, but i never knew her, so i cannot say anything.

I surmise that Duncan and Flora CAMERON were lovely decent
people by the way my grandpa JD Crowley turned out and how he
treated people, a beautiful soul of a man.