I'm sure you're aware that Maria was born in 1850 and Jeremiah jnr in 1872. They are listed in film number 1341862 page 16 which can be viewed at your local LDS church for a small fee - this may reveal Maria's maiden name. Have you tried to get your Grandmother or her siblings death certs?... as these will also give Maria's m.s.
I'm from Scotland but my grandfather was from Laois. The Tom Delaney from Ballinakill that you may have had contact with is possibly on firstname.lastname@example.org