No, Muireann is not a saint name.
The Irish Gaelic version of Raymond is Réamonn;Marian is Marian but the older Irish name Muireann(sea-white, sea-fair) was'translated' as Marian.
Muireann Nic Amhlaoibh was born in 1978.
Muireann Price was born on May 31, 1987, in UK.
No, Irish is not the name of a saint.
Saint Brendan the Navigator
I've never seen the name before:the closest would be Muirenn (in Old Irish) now spelled Muireann (mir-an) in Modern Irish. The name may mean "sea-white, sea-fair".It is true that the meaning is "sea-fair". It is pronounced (Mare-in). Mairenn was a Irish Queen.
There is no saint named Niamh. She is a mythical Irish character.
Patrick brought Christianity to the Irish.
Saint Patrick is the best known of the Irish saints.
Saint Brendan
Saint Cinnia was an Irish princess who was converted by Saint Patrick.