And it appears that the Connacht pronunciation of "Aibreán" and "Aibreáin" are indistinguishable. You just have to know how to spell it in each case to make DL happy.
There is a difference in pronunciation between the slender n in aibreáin and the broad n in aibreán. It's subtle, and not immediately obvious (unless you hear both pronunciations side-by-side).
But as aibreáin is the genitive of aibreán (you use the genitive in a phrase like "the month of April" - Mí Aibreáin), and there is nothing to cause the genitive in a standalone exercise like this, there isn't really much grounds for confusion - you only use the genitive spelling in a genitive phrase.