I searched the Irish Family History Foundation's database. It contains 12,000,000 survivng rcds for abt 65% of Irish Counties. Rcds B4 1840 are sparse, B4 1800 are rare. Co. Louth is in the database. Most parishes, including Collon, are shown as recording birth/baptisms as of your date.
I found 0 B rcds for James Emerson for 1836 and for a wide range of years around this date. I am surprised. The IFHF should have been using the same original sources and/or microfilms thereof as the LDS. There ought to be similar rcds in both. The current database has only RC rcds. All protestant denominations are omitted. Could your ancestors have been protestants?
Looks like you will have to be satisfied with the LDS citation.
For Henry Emerson, I found 0 M rcds.
For Jane McEntire, I found 1 B rcd in 1830 Mayo
For the surname Callaway, I found 413 B rcds in all Ireland. However, 0 had a Louisa forename; in fact none of the forenames even begin with the letter "L."
Google the Foundation's name to lead you to this database. Register, opt to be notified as rcds are added and browse. Pls post your search results to my genforum msg.