Researching Elliott Family

Hello, I have been doing research on the Elliott family and have come to a "dead-end" so I would dearly love some assistance if possible.

My Gr Gr grandfather named Stephen Elliott emigrated on the ship General Hewitt to Australia in 1856. I have his shipping record, marriage record from here in Australia and his death certificate - all state he was born in 1836 and I believe those records have been destroyed. On the certificates it states his father's name was Robert (a farmer) and his mother's name was Fanny. I can not find marriage records for them. 

I have found in the Griffith's Primary Valuations of Ireland a record of some land that was held by a Stephen Elliott and a fellow occupier was a Robert Elliott. This has lead me to wonder if in fact these are my ancestors. 

I also obtained records of children born to a Robert Elliott and Fanny Wilson from 1841 to 1854. Their names are Robert, Alexander, Martha and Mary. Of course my gr gr grndfathers name is not there as it would have been destroyed but I wonder if these children of Robert and Fanny could have been my gr gr grandfathers siblings.

I was wondering if you could tell me if there is any way of finding out if I am on the right track. I really don't know where to go from here to try and prove that they are my ancestors.

We are coming to Ireland in Sept this year and would dearly love to visit where Stephen might have come from.

I look forward to receiving any help/advice you give me

many thanks

Sheryl Prickett  (Brisbane Australia)