Hi...
I can't find a birth in Roscommon for a Winifred Conboy but I did find her marriage - as I am not sure that you know where it took place in Roscommon, I looked it up for you and it took place 1846 in Kilkeevan Church of Ireland, Co. Roscommon.
I did find one child born to Thomas and Honor however...its a Catherine Conboy b. 1826 in Castlerea, Co. Roscommon. I searched all of Ireland for any other children born to Thomas and Honor, but it was Catherine's birth which only came up.
I did find two deaths for a Thomas Conboy in Co. Roscommon also...
Thomas Conboy died 1834 in Athleague, Co. Roscommon and another in 1876, Roscommon Civil (CP). I tried to search for an Honor Conboy but nothing came up.
There are a few Richard Fairbrothers on the NZ Electoral Roll but none with a Richard and Winifred together. However, there is a Winifred Fairbrother on the 1896 Electoral Roll in Wairarpa as a widow. She is also on the 1900 Electoral Roll in same place, and again between 1905 and 1906, and also on 1911 Electoral Roll. I have got the images for all of them - if you want them, I will gladly email them to you if private message me your email address.
Oohh there are a few trees on Ancestry with both Richard and Winifred on there. I don't know if some of them are your trees but one of the trees has pictures of Richard and Winifred. If you have Ancestry..go to public member trees and type in Winifred Conboy and Richard Fairbrother. It looks like the Electoral Rolls are the right ones for Winifred as well.
Hope some of this helps,
Annie