The only book that gives Honora Bourke as the wife of Nich: Malby is “The Family of Brabazon” by W J Brabazon, pub privately in 1825.  The 2003 Burke’s Peerage has nothing on her under the earldom of Clanricarde, though it does not clearly list all the children of the third earl.  CP, of course, is not interested in non-peerage lines.  So a little question mark must be put under this line.